10 JAMES AND OTHERS v. THE UNITED KINGDOM JUGDMENT includes semi-detached and terrace houses but not flats and maisonettes (section 2 of the 1967 Act). 21. The following, in broad terms, are the principal conditions which must be satisfied before the tenant of a house becomes entitled to the right of acquisition conferred by the Act: (a) The tenancy must be a "long" tenancy, that is either for a term certain of 21 years or more or for a lesser term once it has been renewed for periods totalling over 21 years (sections 1 and 3 of the 1967 Act). (b) With certain exceptions not relevant for present purposes, the "rateable value" of the house (that is, the notional annual rental value fixed for local taxation purposes) must not exceed £750, or £1,500 if the house is in Greater London (section 1 of the 1967 Act as amended by section 118 of the 1974 Act). The original rateable-value limits fixed in the 1967 Act (£200 and, for Greater London, £400) were revised (in effect being raised to £500 and £1,000, respectively) by the 1974 Act to take account of the country-wide rating revaluation carried out in 1973. The 1974 Act further extended the scope of the enfranchisement scheme under the 1967 Act by bringing in houses of a still higher rateable value (between £500 and £750 and, for Greater London, between £1,000 and £1,500), in respect of which, however, a different purchase price was payable (see paragraph 23 below). Certain even more valuable properties, being outside the global rateablevalue limits, remain outside the ambit of the legislation altogether. (c) The annual rent must be a "low" rent, that is less than two-thirds of the rateable value (sections 1 and 4 of the 1967 Act). (d) The tenant must occupy the house as his only or main residence and must have done so for at least three years prior to the time when he gives notice of his desire to exercise his rights under the Act (section 1 of the 1967 Act as amended by section 141 and schedule 21 of the 1980 Act - the 1967 Act originally provided for a five-year minimum period). 22. Where the above conditions are satisfied the tenant has two rights: (a) he can obtain a fifty-year extension of the lease at a rent representing the letting value of the ground (without buildings), the rent being subject to revision after 25 years (sections 14 and 15 of the 1967 Act); (b) he can purchase the freehold on the terms outlined below (section 8 of the 1967 Act). The tenant can set in motion the procedure for exercising his right to purchase the freehold at any time up to the original term date of the lease, but not thereafter (section 16 of the 1967 Act). 23. No price or premium is payable for an extended lease other than the rent. On the purchase of a freehold, a price is payable to the landlord as determined in accordance with one or other of two bases of valuation. These are referred to as the "1967 basis of valuation", which was introduced by the 1967 Act (as amended by the 1969 Act), and the "1974 basis of valuation",