Voters are going to the polls at a west London by-election today against a backdrop of economic austerity and clashes over Britain's place in Europe.
Labour leader Ed Miliband claims the Feltham and Heston vote will give constituents an opportunity to pass their verdict on David Cameron and George Osborne's "catastrophic" handling of the economy.
But the Prime Minister has enjoyed a notable boost in the polls since he blocked European treaty changes to shore up the single currency last Friday.
And on Wednesday he mocked Labour, claiming it was united in wanting one thing for Christmas, "a new leader".
The parliamentary by-election was sparked by the death last month of veteran Labour MP Alan Keen after he lost his battle with cancer.
Labour has held Feltham and Heston, a suburban constituency near Heathrow Airport, since 1992. At the 2010 general election, Labour's majority in the west London seat was cut to 4,658 thanks to a 4.8% swing to the Tories.