The Social Security (Medical Evidence) Regulations 1976

[F113.  Where—

(a)the patient has been advised by a doctor that they are not fit for work and, in consequence, has refrained from work for at least 6 months immediately preceding the date of the assessment on which the doctor’s statement is based; and

(b)in the doctor’s opinion, the patient will not be fit for work for the foreseeable future,

instead of specifying a period, the doctor may, having regard to the circumstances of the particular case, enter, after the words “case for”, the words “an indefinite period”.]