Part time work: are you being treated less favourably?

There are many reasons why you may choose to work part time. It may be that your employer can only offer part time hours due to lack of business, or despite your best efforts, you may only be able to find part time work. Alternatively there may be non-economic reasons such as the lack of affordable or adequate childcare, existing family or personal obligations, health or medical limitations, or other commitments such as to study. Whatever your reasons for taking a part time job, it is important to know that you have the right to be treated on the same terms as a full time worker. If you are treated on less favourable terms to a full time counterpart, you may be able to bring a claim.

In this article I provide an overview of the law in relation to the treatment of part time workers and explain when you might have grounds to bring a claim.

What is the relevant legislation? (law)

Where a part time worker finds that they are being treated less favourably than a full time worker and this cannot be ‘objectively justified’, they can challenge this using the Part-Time Workers (Prevention of Less Favourable Treatment) Regulations 2000 (SI 2000/1551). This applies to all workers – not just employees.

Prior to this legislation coming in to force in July 2000, a part time worker who was treated less favourably would have to bring a claim for sex discrimination or equal pay. As an example, if a part time worker was passed over for promotion (due to them working part time), they might claim indirect sex discrimination because part time workers are more likely to be women. Of the 15.3 million women employed in the UK, 41% are part time workers, compared to 13% of men (Source: Women and the Economy Briefing Paper, March 2019). Logically, therefore, where part time workers are treated less favourably, this affects women disproportionately – even if the measures apply to both genders.

It is still possible to bring a sex discrimination or equal pay claim, but it will usually be cheaper and simpler to use the Regulations. However, if the worker’s problem is that their employer will not allow them to switch from full time to part time work (for example, so that a mother can fulfil her childcare commitments), the Regulations do not cover this and she will still need to bring an indirect sex discrimination claim.

What does the legislation say?

The essence of the Regulations can be found at Section 5 which says:

5. (1) A part-time worker has the right not to be treated by his employer less favourably than the employer treats a comparable full-time worker—

(a) as regards the terms of his contract; or
(b) by being subjected to any other detriment by any act, or deliberate failure to act, of his employer.

(2) The right conferred by paragraph (1) applies only if—

(a) the treatment is on the ground that the worker is a part-time worker, and
(b) the treatment is not justified on objective grounds.

Source: The Part-time Workers (Prevention of Less Favourable Treatment) Regulations 2000

Who does the legislation apply to?

The Regulations apply to full time and part time workers.

  • ‘Part time’ means that the person is paid by reference to the time that they work, and the person does not work the same hours as those the employer considers to be full time (Regulation 2(2)).
  • ‘Full time’ means that the person is paid by reference to the time that they work, and the person works the hours that the employer considers to be full time (Regulation 2(1)).
  • ‘Worker’ means a person who works either under a contract of employment, or under another type of contract for the personal performance of work or services. It does not cover people who provide those services on a professional basis or as a business (Regulation 1(2)).

What is ‘less favourable treatment?’?

Female business person

Less favourable treatment may include being overlooked for a promotion, lower pay or less favourable benefits, for example.

Less favourable treatment means less favourable contract terms or any other detriment or act, or failure to act, by the employer – in comparison to a full time worker.

The treatment must be on the grounds that the worker is part time, rather than some other objective grounds. As an example, if two workers are up for a promotion – one full time and one part time – and the full time worker is given the promotion because they work full time, that would be less favourable treatment. On the other hand, if the full time worker is given the promotion because the part time worker has performance issues, this would be some other objective ground that does not relate to the worker’s part time status.

A good example can be found in Hendrickson Europe Ltd v Pipe EAT/0272/02. In that case Mrs Pipe, one of four accounting assistants at the business, had switched from full-time to part-time hours (28.5 per week). Her employer then decided that it only wanted to employ three people full-time and Mrs Pipe was pressured to return to full time hours. She reluctantly offered to increase to 32.5 hours, just 5 hours less than a full time role, but her employer did not properly consider her offer and insisted she must take 37.5 hours. When she refused, she was dismissed. The employer said that the reason for dismissal was a need for it to have three full-time accounting assistants. However, the EAT (upholding the employment tribunal’s decision) found that she had been treated less favourably due to her part-time status.

The EAT provided some useful guidance as to how to consider matters under Regulation 5:

  • What is the treatment complained of?
  • Is that treatment less favourable than that of a comparable full-time worker?
  • Is the less favourable treatment on the ground that the worker was a part-time worker?
  • If so, is it justified on objective grounds?

In deciding whether treatment is ‘less favourable’ a tribunal must ask whether a reasonable person would consider they had been disadvantaged in some way in relation to this particular term of engagement. Of note, less favourable treatment cannot be offset or cancelled out by some other more favourable treatment of a different type. The tribunal must consider each term of the contract in isolation, rather than viewing the part time worker’s contract as a package. For example, in the case of Matthews (below), full time firefighters received a pension but retained part-time firefighters did not. The Fire Authority argued that the part time firefighters received annual bounty payments instead – however, the Tribunal held this ‘package’ approach to evaluating contract terms was incorrect and stated that each benefit should be compared on a term-by-term basis (it also noted that the pensions afforded to full time firefighters included death in service benefits which could not be replicated in the bounty payment in financial terms).

How do I establish that I have suffered ‘less favourable treatment’?

To establish less favourable treatment, you need to find a full time worker to compare to. This person must be:

  • A full-time worker at the same establishment (not simply someone who works more hours than the claimant)
  • With the same type of contract
  • Who does the same or broadly similar work

Hypothetical comparitors

If no worker can be identified that satisfies these three requirements, a claim can be based on someone working at or based at a different establishment (Regulation 2(4)).

Generally it is not possible to use a hypothetical comparator – there must be a real, full-time comparator for the purpose of the claim. This is where the Regulations differ from discrimination claims which allow hypothetical comparitors. However, provided that a comparitor can be found, tribunals can also consider hypothetical comparitors in reaching a decision. A hypothetical comparator can also be used if the worker wants to compare their previous full time status with their new part time status.

Same type of contract

When looking at whether the comparitor has the same type of contract, there are a number of distinct types listed at Regulation 2(3):

(a) employees employed under a contract that is neither for a fixed term nor a contract of apprenticeship;
(b) employees employed under a contract for a fixed term that is not a contract of apprenticeship;
(c) employees employed under a contract of apprenticeship;
(d) workers who are neither employees nor employed under a contract for a fixed term;
(e) workers who are not employees but are employed under a contract for a fixed term;
(f) any other description of worker that it is reasonable for the employer to treat differently from other workers on the ground that workers of that description have a different type of contract.

Source: The Part-time Workers (Prevention of Less Favourable Treatment) Regulations 2000

Part time workers need to identify someone who falls within the same group as them. So for example if the part time worker is an employee apprentice (Regulation 2(3)(c)) they cannot use a full time worker who is not an apprentice (Regulation 2(3)(a)) as a comparitor. They instead need to find a full time employee apprentice to compare to, and assess whether they are being treated less favourably than that person.

However, a part time worker with a fixed term contract CAN compare themselves to a full time worker with a permanent contract. Fixed term and permanent contracts are not viewed differently.


In Roddis, a lecturer with a zero hours contract was able to use a full time employed lecturer as their comparitor. 

Zero hours contracts would appear at first glance more tricky when it comes to finding a comparitor. In Roddis v Sheffield Hallam University UKEAT/0299/17 it was held that a zero-hours contract is not in itself a different type of contract (in other words, a worker with a zero hours contract can compare themselves to a full time employee). However in Wippel v Peek & Cloppenburg GmbH & Co KG C-313/02 [2005] IRLR 211 (heard under the Framework Agreement rather than the Regulations) the ECJ would not allow a full time employee to be used as a comparitor because the part time worker was engaged for ‘work on demand’ and was paid for the hours worked, refusing work if she wanted to. By contrast her full time employed colleagues were obliged to work a fixed number of hours for a fixed salary and couldn’t refuse work. The difference in treatment she complained about was the very reason she could not identify a suitable comparitor – her full time employed colleagues did not enjoy the same level of freedom! Of note, the House of Lords described her claim as outrageous, as she was in effect seeking the same pay as a full time employee, even if engaged for zero hours.

This may be compared to the Roddis case which succeeded on appeal because the claimant did not seek to be paid a full-time salary regardless of the number of the hours he worked, and his claim was not clearly outrageous. Unlike Wippel, the claimant did not have the freedom to work when he chose – if he accepted an offer, he had to provide a course for the length of the course. Further, the broad characteristics of the claimant’s zero hours contract and that of his comparitor, a full time employee, were the same. Both had notice periods and enjoyed statutory protection from unfair dismissal due to length of service. It is important to appreciate that if courts rule that the contracts were not the same due to the part-time worker’s hours of work, the entire legislative purpose would be defeated since a worker would never be able to find a comparator suitable for applying the Regulations.

Switching to part time or returning to work

Although in most cases it will be necessary to find a full time comparitor, this is applied differently where the worker is switching from full time to part time. In such cases, the worker can compare their new terms to those they had immediately before the switch – even if their new contract is not of the same type (Regulation 3).

The same rules apply if the worker switches to part time after being away for some time. A good example is if the worker has taken maternity leave or a career break. If they return to the same job, or a job at the same level, following a break of less than 12 months, they can compare their terms to those they held previously as a full time worker, rather than having to find a comparitor.

The same or broadly similar work

Fireman at work

In Matthews, retained fireman and full-time fireman were found to carry out the same or broadly similar work for the purpose of the Regulations. Image: George Rex.

In considering whether the full time comparitor does the same or broadly similar work, it is worth looking at the case of Matthews and others v Kent and Medway Towns Fire Authority and others [2006] UKHL 8 mentioned above, concerning 12,000 retained firefighters who claimed they were being treated less favourably in comparison to full time firefighters.

A retained firefighter works part time and may be called on to respond to an emergency. A full time firefighter by contrast will have additional duties, with different working patterns and a different level of qualifications/skills. In addition to putting out fires, they also do educational, preventative and administrative work. It would seem that the two therefore do not carry out the same or broadly similar work. However, when the case reached the House of Lords, it disagreed, holding that the main purpose of both full time firefighters and retained firefighters is the same (putting out fires). The House of Lords the view that where a large component of the work was the same, the question should be whether any differences were of such importance that they prevented the work from being regarded as the same or broadly similar. The correct approach is to give weight to how the roles are the same and how importance that is to the enterprise as a whole. If any other approach were taken, too much weight would be given to factors that are an inevitable consequence of working part time. Consequently on remission from the House of Lords, the tribunal found that the retained firefighters did indeed carry out the same or broadly similar work as the full-time firefighters.

Sole or predominant reason for unfavourable treatment

Where an employer treats part time workers less favourably, it may argue that this was due to some other reason unrelated to their part time status. But what if there is a combination of reasons for the treatment? Here the law differs between England and Wales, and Scotland.

In Scotland, the fact that the worker is part time must be the SOLE reason for the less favourable treatment, if a claim is to be successful (Gibson v Scottish Ambulance Service EATS/0052/04).

However, in England, a claim under the Regulations is possible if the worker’s part time status is ONE OF the reasons for the less favourable treatment (Sharma and others v Manchester City Council [2008] IRLR 336 (EAT), followed in Carl v University of Sheffield UKEAT/0261/08). In Carl v University of Sheffield, the tribunal held that the part time status of the worker must be  the “effective and predominant cause” of the less favourable treatment.

Applying the pro rata principle

When comparing the benefits of a full and part time worker, the pro rata principle must be applied unless it is inappropriate to do so (Regulation 5(3)). Somewhat logically, any pay or benefit received by the part time employee should be proportionate to their number of hours. So for example if a full time employee works five days a week and gets 30 days holiday each year, a part time employee working three days a week should receive 18 hours (30 divided by 5, times 3). Note however that the fact benefits have not followed this principle does not automatically mean there will be a successful claim – you’ll still need to show that the worker’s part time status was the effective and predominant cause of the employer failing to follow the principle.

Dealing with overtime

Many companies pay an enhanced rate for working overtime. Part time workers should get the enhanced rate once they have worked the same hours as a full time employee would have to work to get that rate (Regulation 5(4)). As an example, if the employee is paid for the first 40 hours of the week at standard rate and anything over that at time-and-a-half, the part time worker must complete 40 hours that week before they qualify for time-and-a-half – even though this will involve more hours than they are usually contracted for.

If the company pays nothing for overtime (for example, if they state the first 10 hours over their normal working hours each month is unpaid) this breaches the equal pay provisions contained in the Equality Act 2010. The reason for this is that it would be more difficult for part time workers to meet the threshold and therefore such a policy would indirectly discriminate against women who, as stated earlier, are more likely to work part time. The policy will of course be discriminatory unless the employer is able to objectively justify their policy on some other grounds.  See Elsner-Lakeberg v Land Nordrhein-Westfalen (C-285/02) [2005] IRLR 209 and Voss v Land Berlin (C-300/06) [2007] ECR I-10573.

Public and bank holidays

Although holiday is generally apportioned according to the part time worker’s hours, a layer of complexity is added by bank holidays. Many employers give these on top of the normal statutory holiday entitlement. However, most bank holidays fall on a Monday and some part time workers do not work Monday. Employers can ensure there is no discrimination by giving the part time worker pro rata entitlement to all public holidays, even if it is not a day they usually work on. In other words, add the bank holidays to the standard holidays, then perform the pro rata calculation based on the number of days the part time worker is contracted for.

Insisting that a part time worker has no entitlement to the bank holidays if that is not their usual working day, won’t automatically be unfair. Again, the employer needs to show that the reason for this potentially less favourable treatment does not relate to the worker’s part time status, or that the treatment is justified.

What next?

The above is intended to be a brief overview of the law in relation to part time workers and less favourable treatment. It is not a substitute for professional advice. If you believe you are being treated less favourably due to your part time hours, speak to a solicitor for advice.

About Jen Wiss-Carline

Jen Wiss-Carline has been a Senior Manager and Consultant for several sizeable companies which included dealing with all aspects of staff management and recruitment. She is also a Chartered Legal Executive, and was admitted as a Fellow in February 2006.

Jen's qualifications include:
LL.B (Hons) (1st)
Chartered Legal Executive (FCILEx)
PG Cert Bus Admin
PgDip Law (LPC)
LL.M (Master of Laws) (Distinction)

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