SHADOW Chancellor George Osborne insisted he was "relaxed" last night, despite facing a “sleaze” probe over his expenses claims.

A complaint lodged by the chairman of the Labour Party in his Tatton constituency will be investigated by the Parliamentary standards commissioner, it was announced.

It follows allegations Mr Osborne took out a taxpayer-funded mortgage on his constituency home that was nearly £5,000 more than its purchase price.

Documents sent to the commissioner, John Lyon, allegedly show Mr Osborne paid £445,000 in cash for his Cheshire farmhouse, while a mortgage account summary statement showed him claiming for £450,000.

In a statement, Mr Lyon said he would look into a claim "Mr Osborne claimed for mortgage payments that were not necessarily incurred, contrary to the rules of the House".

However, the commissioner said that he would not inquire into whether the Shadow Chancellor had "flipped" his second home and avoided paying capital gains tax – insisting they were matters for Revenue and Customs. Last night, Labour backbencher John Mann said Mr Osborne would have to "immediately resign his position", if the investigation found against him.

But a spokesman for Mr Osborne hit back, insisting he had acted with the approval of the fees office and criticising "a political complaint by the local Labour party".

He added: "George is relaxed about it. There has been absolutely no impropriety and any suggestion of such is wrong.”

"His actions have been entirely reasonable.”