Croydon Central MP Gavin Barwell has narrowed the gap in the race to win the key marginal seat but still trails Labour's Sarah Jones, polls suggest.

Lord Ashcroft's latest snapshot puts Mrs Jones four percentage points ahead of the incumbent Conservative, down from six in October.

Both Conservatives and Labour have actually gained support in the constituency, the poll indicates, with Ukip and the Lib Dems losing ground.

The results came as the battle for the seat, predicted to be one of the country's most closely contested on May 7, heated up this week.

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Mrs Jones's campaign hit full pelt as she published her election pledges during a 24-hour marathon tour of Croydon on Monday.

And Mr Barwell hit the headlines on the same day - although for less welcome reasons.

The Conservative's request for friends or neighbours to endorse him backfired after the Evening Standard seized on the line: "I'm not asking you to write a political letter - in fact, it'll be much more effective if it doesn't mention the Conservative Party or David Cameron."

Mr Barwell dismissed the story - which made the front page of the paper's early edition - as "utterly ridiculous", tweeting: "Card we leave at every door we call on has photo of PM on it". 

Croydon Central voting intention (Lord Ashcroft polls, March 2015)

Labour 41 per cent 

Conservative 37 per cent 

Ukip: 13 per cent 

Liberal Democrat: 3 per cent 

Green: 5 per cent

Other: 1 per cent

For more on the General Election visit www.croydonguardian.co.uk/generalelection2015