10E+W+SA person subject immediately before the commencement of section 61 of this Act to a licence under any of the following enactments, that is to say, section 27 of the M1Prison Act 1952, section 21 of the M2Prisons (Scotland) Act 1952 (persons serving imprisonment for life), section 53(4) of the M3Children and Young Persons Act 1933 or section 57(4) of the M4Children and Young Persons (Scotland) Act 1937 (young offenders convicted of grave crimes), shall be treated as if he had been released on licence under the said section 61 and as if the conditions contained in a licence under any of the said enactments had been specified in a licence under the said section 61 and, in the case of a person released after being sentenced under section 53(2) of the said Act of 1933 or section 57(2) of the said Act of 1937 to be detained otherwise than for life, as if a licence granted to him under the said section 61 had specified the date of the expiration of his sentence as the date until which the licence is to remain in force.