Suppose you have an assured tenancy for a year from 19 January. The agreement provides for a monthly rent payable in advance on the first of each month. On the expiry of the fixed term, a statutory periodic tenancy arises. But, are the monthly periods of the tenancy from the 19th to the 18th, or from the first to the last day of the month? The answer is unclear. There are two conflicting county court cases. In Baynes [2005] it was said the actual date on which the rent falls due is irrelevant, it makes no difference to the date on which a valid s21 notice should require possession. On this basis, the period of the tenancy would be from the 19th to the 18th. But, Vodecca [2005] took the opposite view.

If you are wondering why this question is important, the answer lies in (a) s21(4) HA 1988 which says that a notice requiring possession served after the end of a fixed term tenancy must require possession after a day which is the last day of one of the periods of the tenancy (although, in practice, a ‘saving clause’ notice would solve that problem), and (b) if a notice of rent increase is served under s13 HA 1988, then the proposed new rent must be from the start of a period of the tenancy starting not less than than a minimum period in the future (ie getting the date wrong could mean that a notice of increase was invalid). Source: Nearly Legal (http://nearlylegal.co.uk/blog).