The maximum term of imprisonment to which a person is liable if convicted on indictment of an offence under section thirty of the Sexual Offences Act, 1956 (man living on earnings of prostitution), or under section thirty-one of that Act (woman exercising control over prostitute) shall, for offences committed after the commencement of this Act, be seven years; and accordingly, for offences so committed, in the Second Schedule to that Act, in items 30 and 31, " seven years " shall be substituted for " two years " in the third column.