Been Off Work?
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 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).
It is up to your employer to decide whether you are incapable of work. A medical certificate, now called a 'Statement of Fitness for Work’ (see below) from your doctor is strong evidence that you are sick and would normally be accepted, unless there is evidence to prove otherwise.
You could also provide evidence from someone who is not a medical practitioner, e.g. a dentist. Your employer will decide whether or not this evidence is acceptable. If your employer has any doubts, they may still ask for a medical certificate from your GP.
Statement of Fitness for Work - ’Fit Note'
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)
Short Term Certification
We are aware that some employers sometimes ask employees to provide medical evidence to support sickness claims for periods of less than one week.
Please note that GPs are not required by law or by their contracts to provide sickness certificates for periods of less than one week. This practice does not provide such certificates under any circumstances. This is because we wish to discourage people from making appointments purely to obtain a certificate, when those appointments could be better used by other patients. We will, of course, see patients who need medical advice but we will not issue short term certificates.