For periods of 4-6 days sickness—your employer may require you to complete a self-certification form SC2 which is available from your Employer, at reception or the D.S.S.
For illness longer than 6 days—you will need to see the Doctor for him/her to issue a sickness certificate and for any subsequent renewal of the certificate. The only exceptions to this may be after hospital inpatient or outpatient attendance or for long-term sickness.
The law states that you do not need to obtain a certificate from your Doctor for illness between 1—6 days. If your employer insists that you obtain one, this service is not covered by the NHS and a charge may be made.