21. After the end of the period of 5 years beginning with the day on which this Order comes into force—
(a)no notice to treat is to be served under Part 1 of the 1965 Act, as applied by article 17; and
(b)no declaration is to be executed under section 4 of the Compulsory Purchase (Vesting Declarations) Act 1981, as applied by article 18.