You do not require a doctor’s sickness certificate for any illness lasting seven days or less. Your employer may however require you to complete a self-certification form (SC2) which is available from your employer or on the HNRC website.
Evidence that you are sick
If you are sick for more than seven days, your employer can ask you to give them some form of medical evidence to support payment of SSP (Statutory Sick Pay). Most employers ask for a Fit Note from your GP. However, this may depend on your company’s sick leave policy
Statement of Fitness For Work “Fit Note”
This was introduced in April 2010. With your employer’s support, the note will help you to return to work sooner by providing more information about the effects of your illness or injury.