Head of the River Race only open to men's eights and is considered to be the peak of the head race season — attracting the top UK crews as well as foreign clubs. Composite crews, drawn from more than one club or institution, are not permitted. The Championship Course is that of the Oxford and Cambridge Boat Race but, unlike the Boat Race, the Head of the River Race is raced on an ebb tide from Mortlake to Putney. The starting time for the race is different every year and depends on the tide — the first crew (winner from the previous year) starts the
Mortlake of the Council. Richmond Park, the constituency which includes Mortlake, had changed from Liberal Democrat to Conservative in the 2010 general election, was recaptured by the Liberal Democrats in the 2016 by-election, and finally reverted to Conservative MP Zac Goldsmith in the 2017 general election by a margin of only 45 votes. The London Assembly constituency South West, which includes Mortlake, is represented by former local councillor Tony Arbour (Conservative). The place-name 'Mortlake' is first attested in the Domesday Book of 1086, where it appears as "Mortelaga" and "Mortelage", a name with two possible derivations. If the second element is