What Is Classed as Long-Term Sickness?

It’s estimated that around 15 million people in the UK – that’s around 30% of the population – suffer from at least one long-term health condition. Managing day-to-day life while also coping with fluctuating health and ongoing symptoms can be challenging, especially when you’re also trying to balance workplace responsibilities. This can result in difficulties for both the employer and the employee, leading to reduced productivity, excessive workloads and increased pressure on other employees.

To ensure long-term sickness is handled sensitively, fairly and legally it’s important to understand what long-term sickness actually is, how it should be managed and what an employer’s legal responsibilities are. To help, the team here at Healthier Workforce has written this guide detailing what you need to know.

What is long-term sickness?

Long-term sickness is exactly as it sounds; it’s a period of extended absence from work due to an ongoing health condition, illness or injury. While there is no universal legal definition of what is classed as long-term sickness, most employers generally consider it to be any absence lasting longer than four weeks.

Common causes of long-term sickness

According to the 2025 CIPD Health and Wellbeing at Work survey of 1,101 employers, the top five causes of long-term sickness were found to be:

• Mental health issues: This covers a wide range of mental health conditions, such as anxiety, depression, PTSD, bipolar disorder, OCD and more. As the most common cause of long-term sickness, this suggests that some employers may need to prioritise mental health support.
  
• Musculoskeletal injuries: RSI, back pain, joint problems and other musculoskeletal injuries can be exacerbated by strain, repetitive tasks and poor workplace conditions, making it difficult for normal duties to be carried out without adjustments.
  
• Other long-term health conditions: Cancer, respiratory illnesses, autoimmune conditions and other long-term health problems often require ongoing monitoring, surgery and treatment, meaning an extended absence from work may be required.
  
• Stress: Extreme stress can have a hugely negative impact on both your physical and mental health, leading to burnout if left unaddressed.
  
• Acute medical conditions: Serious health events such as a stroke, heart attack or major infection will typically require a prolonged absence from work in order to fully recover.

It’s also important to note that neurodivergent conditions – such as ADHD, Autism, Dyspraxia, Tourette’s Syndrome and more – can contribute towards long-term sickness if the appropriate support is not in place. Sensory overload, inflexible working patterns and a lack of reasonable adjustments can increase stress and lead to burnout and other health difficulties.

What is the law on long-term sickness?

Without proper protections, employees suffering from long-term sickness may be at risk of unfair treatment and discrimination. To prevent this, the UK has several legal frameworks in place to ensure employers provide the necessary support, including:

• Statutory Sick Pay (SSP): If you’re on long-term sick leave, your employer is obliged to pay you the Statutory Sick Pay (SSP) for up to 28 weeks, provided you meet the eligibility criteria. The legal minimum rate is currently set at £118.75 per week, but after this ends, you may be able to apply for additional government support, such as Employment Support Allowance (ESA) or Universal Credit, depending on your circumstances. Some employers may also offer enhanced sick pay schemes that pay out a higher rate or extend the period of support, so it’s best to check your employment contract for specific details.
  
• The Equality Act 2010: If you’ve been off work with long-term sickness that’s due to a disability then you’re legally protected under the Equality Act 2010, and your employer has a duty to “make reasonable adjustments to remove that disadvantage.” This might include flexible working hours, modified equipment or workstations, reduced workloads and additional time off for medical appointments.
  
• Employment Rights Act 2025: Under the Employment Rights Act 2025, any employee who has been at a company for more than two years is protected from unfair dismissal. This means you can’t sack someone solely because they’ve been off on long-term sick leave – the proper legal process must be followed. While dismissal may be considered if an employee is genuinely unable to perform their role, it must be a last resort. Before taking such action an employer must:
• • Carry out a thorough consultation with the employee about their situation
  • Gather advice from medical professionals and occupational health specialists
  • Consider alternative roles within the company
  • Explore all reasonable adjustments
  • Follow all company policies as laid out in their employee handbook or HR procedures.

Then, and only then, is dismissal considered a viable option. 

Failing to abide by the above laws could see an employer facing legal action for unfair dismissal, discrimination or a breach of employment law. This could result in hefty financial penalties, not to mention reputational damage.

How long can you be on long-term sick leave?

There is no universal maximum term for how long an employee can be on sick leave, and it entirely depends on the policies of the company in question. As we’ve mentioned above, you’re entitled to up to 28 weeks of SSP, but you must produce medical evidence for this. You’re allowed to self-certify for your first seven days of illness, but any absence longer than this will typically require a fit note from your doctor. Fit notes are issued at the doctor’s discretion and can last for up to three months at a time, but they must be reviewed and renewed if a longer absence is required.

How to manage an employee after long-term sickness

When an employee returns after long-term sick leave, you can’t just throw them straight in at the deep end and expect them to carry on as normal – careful planning and a supportive approach are needed. The following tips can help to ensure a smooth and stress-free return to work for everyone involved:

• Be understanding yet professional: Your employee has been through a difficult time, so it’s important to be empathetic towards their situation and offer support while they adjust. However, you should also remain professional and set clear expectations so they understand just what’s required of them.
• Carry out an occupational health assessment: If your employee is returning to work after a long period of illness then an occupational health assessment is crucial. During this evaluation, an occupational health specialist will confirm whether or not an employee is fit to return to work, identify any limitations they have and evaluate what kind of support and adjustments – if any – are required.
• Implement a phased return: By putting a phased return in place, you can ensure your employee is eased back into their regular duties gradually, rather than taking on too much too soon and ending up back at square one. You can read our previous guide on phased returns for more information.
  
• Hold regular check-ins: By maintaining open communication and holding regular check-ins with your employee, you can see how they’re coping and identify whether any additional support is needed. If they have any concerns or issues, raising these at an early stage means they can be promptly dealt with rather than escalating.
  
• Make reasonable adjustments: As we’ve covered above, by making reasonable adjustments where appropriate you can support your employee’s recovery and enable them to perform effectively. Not only does this reduce the risk of further absences, but it also ensures you’re complying with the Equality Act 2010.
• Work with a trusted occupational health expert: Working with trusted, experienced occupational health specialists, like the team here at Healthier Workforce, makes managing long-term sickness much more straightforward. Our experts will help to ensure employees are able to safely and effectively return to work, or provide practical advice if a full return to normal duties isn’t possible.

How can Healthier Workforce help?

Managing long-term sickness can be complicated, but when you choose to work with Healthier Workforce, we’ll ensure the process is as simple and straightforward as possible. Whatever you need – whether that’s an occupational health assessment, ongoing health surveillance, sickness absence management or just a bit of advice on how to support employee wellbeing – we’ll be there to support you.

Since 2009, we’ve been working with businesses nationwide, offering a whole host of occupational health services that will help you to build a healthier and more productive workforce. If you’d like to know more about what we do, why not give our friendly team a call. Alternatively, you’re welcome to fill out our online referral form.