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.
For the first 6 days that you are unable to work through sickness you can complete a self certification form. this form can be obtained from your employer or the surgery.
If you are in hospital, they will provide you with a sick note. They should also include any period necessary after you leave hospital. If necessary, this can be extended by your GP when you return home.
After the first 7 days, you will need a sick note from your GP. If necessary, this can be backdated to ensure continuity of sickness absence so an immediate appointment is not necessary.
When you know the date you are returning to work, we can often give you a 'Return to Work' note on request.
If you want to see your doctor solely to extend a sick note, please check with the receptionist whether an appointment is necessary.
If you want a note to confirm sickness within the first 6 days of absence this will require a private note for which a fee is due.
The 'fit note' was introduced on 6 April 2010. With your employer's support, the note will help you return to work sooner by providing more information about the effects of your illness or injury.
For more information see the DirectGov website (where this information was sourced).