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Part-Time Workers' Rights: Understanding Regulations and Legal Protections

A part-time worker is someone who works fewer hours than a full-time worker having regard to the employer’s custom and practice.  There is no specific number of hours that makes someone full-time or part-time.  However, a full-time worker will usually work 35 hours or more a week. Those who work part-time are protected against being treated less favourably than equivalent full-time workers on the basis that they’re part-time unless the treatment can be objectively justified.  

Part-Time Work Regulations Explained

The Part-Time Workers (Prevention of Less Favourable Treatment) Regulations 2000 (the regulations) specifically ensure that part-time workers are not treated less favourably than comparable full-time workers. Interestingly, there is no provision which prevents more favourable treatment of part-time workers. There is no qualifying period of service for bringing a claim.  

Who qualifies as a part-time worker?

In common with several other pieces of recent employment legislation, the regulations apply not just to an “employee” but to a “worker”. This wider definition includes anyone employed under any contract, oral or written, under which they agree to perform personally any work or services for the employer.  The regulations are likely to apply, therefore, to agency workers and freelancers as well as employees.  

The regulations will not apply to individuals who can be shown to be genuinely self-employed.

Who is the comparator and what does the law say?

In assessing whether there has been less favourable or detrimental treatment of a part-time worker, the regulations require the worker to compare such treatment with that of a “comparable full-time worker”. “Comparable full-time workers” are workers:  

  • employed by the same employer
  • under the same type of contract as the part-time worker 
  • engaged in the same or broadly similar work as the part-time worker having regard, where relevant, to whether they have a similar level of qualifications, skills and experience; and 
  • based at the same establishment as the part-time worker. 

Suppose there is no comparable full-time worker at the same establishment. In that case, the part-time worker may compare themselves to a full-time worker at a different establishment, provided that the full-time worker at such establishment is:

  • employed under the same type of contract as the part-time worker; and 
  • does the same or broadly similar work as the part-time worker.

The comparable full-time worker does not have to be the same sex as the part-time worker but must be employed by the same employer and employed at the same time as the part-time worker.  

What is less favourable treatment?

The right not to be treated less favourably applies to the terms of the part-time worker’s contract or in relation to being subjected to any other detriment by any act or deliberate failure to act by the employer.  When a tribunal is looking at whether a part-time worker’s contract is less favourable than a full-time worker’s, it takes a term-by-term approach, rather than looking at the contract as a whole.  The tribunal must also be satisfied that the reason for the less favourable treatment is “on the ground that the worker is a part-time worker”.

The tribunal must also apply the pro rata principle in determining whether the worker has been treated less favourably i.e. the part-time worker is entitled to a proportionate amount of the pay or benefit that the full-time worker receives relative to the number of their respective weekly hours.  

Is there a right to work part-time?

The regulations do not go as far as giving a full-time worker the right to become a part-time worker. Neither do they give workers returning from maternity leave or other periods of absence (such as parental leave, long-term absence or a career break) the right to return to work part-time.  

Part-time workers & Sex discrimination

However, employers should be aware of other potential claims that could be brought by employees wishing to return to a part-time position under the sex discrimination legislation.  Unfavourable treatment in relation to part-time working e.g. a refusal to allow a woman to work part-time may give rise to an indirect sex discrimination claim. This involves showing that an employer has applied a provision, criterion or practice (PCP) e.g. the requirement to work full time, that puts women at a particular disadvantage compared to men. The PCP puts the individual at that disadvantage and the PCP is not a proportionate means of achieving a legitimate aim.

In considering whether the refusal to allow part-time work has a detrimental impact on women, the courts and tribunals have accepted that this is the case without requiring statistical evidence as it is acknowledged that more women than men have primary childcare responsibilities which affects their ability to work full time.  Employers should also be aware that if they deny a man’s request to work part-time where a woman’s request would have been granted, he is likely to have a claim for direct sex discrimination.

Part-time workers & Flexible working

For those wishing to work part-time, there is also the statutory right to request flexible working which is now a “day one” right since 6 April 2024.  There is a statutory procedure for the employer to follow including the timescale for considering the request and notifying the employee of the outcome.  The employer must deal with the application reasonably and may only refuse the request for one of the 8 statutory reasons set out in the legislation.  

However, the key issue for an employer to be aware of, if rejecting such a request, is ensuring that the statutory reason is also sufficient to provide a defence to an indirect sex discrimination claim.  If not, even if the employer is able to show that the refusal is for one of the statutory reasons, they could still be liable for an indirect sex discrimination claim.  

Part-time workers & Equal Pay

Part-time workers faced with discrimination in relation to their contractual terms and conditions may be able to bring a claim for equality of terms under the Equality Act 2010. Equal pay applies to all contractual terms not just pay.  However, a detailed discussion about equal pay aspects is beyond the scope of this article.      

The practical effect of the Regulations and the pro rata principle

Employers should as far as possible treat part-time employees in the same way as full-time employees unless there is some objective justification for different treatment.  Examples of the kind of steps that employers should consider to ensure compliance with the regulations include:

  • Pay – Part-timers must receive the same hourly rates of pay as comparable full-timers unless the difference can be objectively justified e.g. on the basis of performance-related pay.
  • Overtime pay – There is no automatic right to overtime pay if a part-time worker works more than their normal part-time hours.  However, once a part-timer has worked more than the normal hours of a comparable full-timer they will be entitled to overtime at an equivalent hourly rate.
  • Benefits – Part-timers should be allowed to participate pro rata in benefit and profit share/share option schemes unless there are objective grounds to exclude them (such as a disproportionate cost to the employer of providing the benefit to part-timers).  It will not be an objective justification that the benefit cannot be applied pro-rata, as in the case of health insurance.  Unless there are other objective justifications, such benefits will have to be granted to the part-timers in full.
  • Holiday - The holiday rights for part-time workers should be comparable to that available to full-timers, calculated on a proportionate basis. So, if a full-time worker on a 5-day week is entitled to 30 days’ annual leave, a part-time worker working 4 days a week should be entitled to 4/5ths of that entitlement, being 24 days.  All workers are of course entitled to a statutory minimum of 5.6 weeks’ annual leave under The Working Time Regulations 1998.

    Bank and Public Holidays are a difficult issue.  The key point is that it will be discriminatory to exclude part-timers from holidays which comparable full-timers are given simply because they are part-timers.  It would be lawful to have a policy under which Bank/Public Holidays are paid for all workers who would ordinarily work on the days on which they fall.  However, because in practice many part-timers will not work on the days on which most Bank and Public Holidays fall (i.e. Mondays), simply applying such a policy to all staff would put such part-timers at a disadvantage.  The best approach and to minimise the risk of a claim is to give disadvantaged part-time workers a pro-rated entitlement to all public holidays. 
  • Maternity/Parental leave – Again, all workers (whether full or part-time) will have the right to the statutory minimum periods of maternity/parental leave. Any enhancements to the statutory entitlements offered to full-time employees must be extended (on a proportionate basis) to part-timers as well.
  • Career break schemes – These should be offered to full and part-time workers on equivalent terms.
  • Training - Part-timers must not be excluded from training. Training should be scheduled so that, as far as possible, part-timers can attend.
  • Redundancy - Employers will need to ensure that the same selection criteria are applied to full and part-timers for redundancy.  It is not possible simply to make part-time workers redundant first (and in any event such a policy is likely to amount to unfair dismissal and sex discrimination).
  • Promotion - Part-time status should not be a barrier to promotion in itself.

Employer’s responsibilities and defence

The employer has a defence to a claim of less favourable/detrimental treatment under the regulations if it can show that such treatment is justified on objective grounds i.e. if there is a genuine business reason or genuine business objective for it and the treatment is both necessary and appropriate to achieve that objective. Employers are likely to have difficulty justifying less favourable treatment solely on cost grounds and will need to demonstrate other factors.

Depending on the reasons for the less favourable treatment, there is always the risk that other claims could be triggered (such as discrimination or constructive dismissal) and employers should take extreme caution when treating part-time workers differently from their full-time staff. Similarly, if an employee brings an indirect sex discrimination claim the employer has a defence if it can show that the PCP is a “proportionate means of achieving a legitimate aim”.  

Contact us for expert employment law advice

We advise on all aspects of employment law including issues related to part-time workers and discrimination in the workplace. We help employers to put in place the policies and procedures to support their employees and business with confidence. We advise on how to prevent issues from arising and how to handle them if they do through our employment investigations service.

We use our exceptional breadth and depth of experience to give clients personalised advice to help manage risk and resolve issues as well as bespoke training tailored to your needs together with the use of our independent HR consultants to put in place systems to monitor, review and minimise the risk of claims.  

Please contact Michael Powner or your usual Charles Russell Speechlys contact if you would like to get in touch.  

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