Under government sick pay regulations, no certificate is required for an illness of three days or less. A self-certificate form should be completed if the illness lasts up to seven days. These are available from Social Security offices, your place of work or can be downloaded from the internet. GPs are not required to issue statements for periods of incapacity for work lasting seven days or less, or for the first seven days of longer spells.
If the illness lasts more than seven days, you will need to obtain a Statement of Fitness for Work from your doctor. If you are seen in A&E or treated in hospital, the Doctors there can issue sick notes as well.