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 HMRC website.
Evidence that you are sick
If you're sick and off work for more than seven days, your employer will probably ask for proof of your illness. Most employers ask for a fit note from your GP.
In order to obtain a sick note from the surgery you will need to have been examined by a clinician. Please book an appointment online. We can only issue a NHS fit note after you have been unwell for 7 days.