You do not require a doctor's fit note for any illness lasting 7 days or less.
If you're sick and off work for more than seven days, your employer will probably ask for a fit note as proof of your illness.
Fit notes are also known as a ‘Statement of fitness for work’ or a ‘Med3 form’. Doctors issue fit notes to record the advice they have given about their fitness for work. 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. They are also used to support payment of SSP (statutory sick pay).
For more information see the DirectGov website (where this information was sourced)
Anonymous Data Collection
From January 2016 the Health and Social Care Information Centre (HSCIC) will start to collect anonymous data on fit notes issued in England. The data will help the Department of Work and Pensions to gain a better understanding of sickness absence and develop policy to help people with health conditions return to work earlier.
The data being extracted will be anonymous and will include; gender, location, number of fit notes issued, number of patients recorded as ‘unfit’ or ‘maybe unfit’ for work, fit note duration, whether workplace adaptations were recommended and health condition type aggregated to high-level diagnosis code.
NO identifiable individual patient information will be extracted. DWP analysts will only have access to anonymous statistics. The data collection will exclude data from patients who have registered an objection subsequently for data not to be extracted.
For further information about this guidance Patient information on plans for collecting anonymous fit note data