58.Sections 5 to 11 make provision for vacancies in Assembly membership and are based on the provisions in Part V of the Local Government Act 1972 for vacancies in the membership of local authorities.
59.A vacancy arises where
	a member resigns;a member fails for six consecutive months to attend a meeting of the Assembly, of one of its committees or sub-committees or of an outside body as an Assembly representative (unless for a reason approved by the Assembly);
	a member whose only qualification for election was the fact that he was a local government elector for Greater London ceases to be such an elector (see further section 20);
	a member becomes disqualified for any of the reasons set out in section 21;
	a person returned as an Assembly member at an ordinary election is also returned as the Mayor; or
	a member is returned as the Mayor at an election to fill a vacancy in that office.
60.A vacancy arising otherwise than on account of death, resignation or automatic disqualification has to be declared by an officer of the Authority charged with that function or by the High Court under section 23. A vacancy in an Assembly constituency is filled at an election held in the constituency on the first past the post basis. The election must be held no later than 35 days after the date on which the vacancy is to regarded as occurring in accordance with section 10 (but Sundays and holidays are left out of account).
61.If a vacancy occurs within six months prior to the date of an ordinary election, no election will be held; instead it will be left unfilled until the next ordinary election of the whole Assembly. However, if the occurrence of a vacancy means that the total number of vacancies exceeds one-third of the total membership of the Assembly, then an election to fill that vacancy must take place.
62.Where a vacancy arises among the London members, it will remain unfilled until the next ordinary election unless the vacancy is of a London member elected from a party list and there are persons on the list who can be chosen by the Greater London returning officer to fill the vacancy.
63.To be eligible to fill such a vacancy, a person on a list must be willing to serve. In addition, if a person on the list is no longer a member of the party concerned, the party may notify the returning officer that the person is not to fill the vacancy.
64.If there is more than one person who satisfies the conditions set out above, then the highest placed of these persons on the list will be returned.
65.The term of office of the persons elected or chosen to fill vacancies will end at the same time as the terms of office of the persons elected at the previous ordinary election.
Commentary on Sections Part I: the Greater London Authority Sections 5 to 11: Vacancies in the Assembly