Voters go to the polls in less than two hours to decide who will be the next MP for Croydon North.
There are 12 candidates. Labour had a comfortable majority in this seat at the 2010 general election.
The by-election comes after the death of MP Malcolm Wicks, who lost his battle with cancer in September, aged 65.
He had been an MP for Croydon North for two decades and held the seat with a 16,483 majority.
More top news
Martin Allen, 15, disappeared on his way home from school in London in 1979 and was never seen again.
Henry was charged following an incident near Jamie's Italian in Greenwich, south east London, on September 14.
Jon Hunt, who founded Foxtons Estate Agents, says his car blew up while his son was still inside.