If you are absent from work between 3 and 6 days, you should complete a Self Certificate SC2 form.
These forms can be obtained from the surgery or by downloading from the following web address http://www.hmrc.gov.uk/forms/sc2.pdf
A statement of fitness for work MED 3 form completed and signed by your doctor is only required when you have been absent from work due to illness, for longer than 6 days. However you may need to see a doctor to be signed fit for work again.
If your Employer requests that you must provide a sick note to cover your first week off work then please note there will be a ten pound charge.