Tory councillor Gurcharan Singh says a recent survey by his party indicates meltdown for Labour MP Virendra Sharma at the next election.
But Ealing's Labour Party replied with a stunning left hook, dismissing the survey as bogus.
Cllr Singh said the survey was conducted by the Ealing Southall Conservative Association via leafleting, with pre-paid envelopes to allow people to respond anonymously.
Results apparently showed 48 per cent of Southall residents saying they will vote Conservative at next year's election, with just 11 per cent voting Labour.
Mr Singh said: "These results confirm what we have known for some time. Labour is haemorrhaging support in Southall as people realise there is a viable alternative in the Conservatives."
Ealing Labour leader Julian Bell poured scorn on the claims, reminding people that Mr Singh defected from Labour to the Tories in 2007.
"Having betrayed voters by switching political parties and not having the courage to face the electorate as Tories they are now trying to distort the truth in a desperate effort to save their skins. Their survey, like them, lacks all credibility. It flies in the face of the facts shown in our most recent local polling, which shows Labour performing very strongly in Southall."
Mr Sharma said: "When the election comes, people will have a choice between the loyal, hard-working Labour candidates and the Tory turn-coat. I have every confidence in the people of Southall when they make that choice."
A defiant Cllr Singh responded: "They can curse me, abuse me and try to belittle me, but the fact is that they are living in the past and we are talking about the future."