http://www.legislation.gov.uk/ukpga/1999/29/section/3/notesTransport planningEconomic developmentReferendumsMayoral electionsPublic fundingExplanatory Notes to Greater London Authority Act 1999Department of the Environment, Transport and the Regions King's Printer of Acts of Parliament2018-08-30 29 11th November 1999 43 Section 3 contains provisions on ordinary elections to the Authority. The first ordinary election will be held on 4 May 2000, unless the Secretary of State exercises the order-making power provided by this section to postpone them to a later date. Subsequent elections will be held on the first Thursday in May in the fourth calendar year following that in which the first ordinary election was held. Subsections (4)(d) and (5) give the Secretary of State the power to introduce a system of early voting for the first ordinary election. 44 Section 4 contains provisions on voting at ordinary elections. The ordinary election for the Authority will consist of a mayoral election, the election of Assembly members in each of the fourteen constituencies and the election of the London members. 45 In the mayoral election, if there are only two candidates, the one with the most votes wins under first-past-the-post procedures. But if there are three or more candidates, a different voting system - the Supplementary Vote (SV) system - comes into play. Voters will be able to indicate their first and second choice for Mayor. How these choices are counted, in order to determine who should be returned as Mayor, is set out in Part I of Schedule 2 to the Act. 46 Candidates for the Assembly will be elected under the Additional Member System (AMS). Voters will have two votes – one for a constituency member and one – known as a London vote - for an individual or political party list. Each of the 14 constituencies will return one constituency candidate elected on the normal first-past-the-post basis. Eleven additional seats in the Assembly will be allocated on the basis of the London vote using the De Hondt formula. This is intended to top up the number of seats for each party in the Assembly in order to reflect broadly their proportion of the London vote. The precise way in which this is done is set out in Part II of Schedule 2 of the Act. A worked example is given below. 47 The way in which the elections of the Mayor and Assembly members interact is the subject of subsections (7) to (10) of the section. The result of the elections of the Mayor and the constituency members must be determined first, so that the calculation (set out in Part II of Schedule 2) resulting from the count of the London vote can be made under section 4 and Schedule 2; this calculation is not to be held up if any of the constituency polls has been countermanded. No-one may stand in more than one Assembly constituency and if the person returned as Mayor is also successful in a constituency election, a by-election will ensue in that constituency (but the seat will be counted as having been won by the relevant party for the purposes of the London vote - see paragraph 6(4) of Schedule 2). More detailed provision for the interaction of the various polls is contained in Schedule 2 to the Act. 48 Schedule 2 contains detailed provisions on voting at elections for the Mayor and the London members of the Assembly.