Sadiq Khan, Mayor of London
Polling experts speak to IBTimes UK about the June by-election after Sadiq Khan's resignationGetty

Labour could lose the London seat of Tooting to the Conservatives if the by-election "takes on a life of its own", a polling expert has claimed. Adam Ludlow, a senior consultant at ComRes, told IBTimes UK that the phenomenon of gentrification could also play a role in the vote.

"If you look at what's happened in Tooting, it was once a safe Labour seat but it has been getting gradually more marginal over the long-term. Most people attribute that to demographic changes, with more affluent young people moving in [to the seat], which could help the Conservatives," he explained.

"Added to that, by-elections as a whole can tend to take on a life of themselves – they don't always follow the usual script. Isolated factors can take over and obviously with lots going on in politics at the moment that certainly could be a possibility, whether it be the EU referendum or Jeremy Corbyn's leadership."

But Ludlow stressed it was very hard to determine who would come out on top of the by-election without conducting any polling. He also referenced the 5 May elections, which saw Labour gain the Merton and Wandsworth London Assembly seat from the Tories.

The Tooting by-election was triggered after Sadiq Khan stood down from the House of Commons, after the success of his campaign to become Mayor of London. A source told IBTimes UK that the vote will be held on 9 or 16 June, and a shortlist of Labour hopefuls will be drawn up on 11 May.

The candidates will take part in a hustings on the same day, after which local members will vote on who will become the party's prospective parliamentary candidate for the seat. Labour has held the constituency since its creation in 1974.

However, Kahn secured a majority of just 2,800 at the general election with 47% of the vote, while Conservative hopeful Dan Watkins garnered 42% of the vote. Anthony Wells, director of YouGov's political and social opinion polling, was bullish about Labour's chances of retaining the seat.

"It's extremely, extremely rare for the government to win an opposition seat in by-elections – it last happened in 1982," he told IBTimes UK. "The only way I could see [a Tory victory] is if Labour really muck up their selection in some way. I doubt Labour will."

Wells also said that he expected Labour to increase their share of the vote in the seat. "Just because it's a mid-term election, they're the opposition, there shouldn't be any major fuss," he argued.

None of the major parties have announced their candidates for the by-election, but Respect leader George Galloway has teased on Twitter that he might run. The former MP came seventh, behind Women's Equality Party hopeful Sophie Walker, in the Mayor of London election with 37,000 votes.

London mayor election 2016: George Galloway promises to purge Transport for London top brassIBTimes UK