Millionaire Birmingham MP John Hemming said he had done nothing wrong after it emerged he used the Parliamentary expenses system to pay off a mortgage on an office in the city.

The Liberal Democrat Yardley MP took out a £200,000 mortgage on a Covent Garden flat and used the cash to pay off what he owed on offices in Alcester Road, Moseley.

He claimed £825-a-month in Commons expenses for interest on the London mortgage – but did not break House of Commons rules because he was entitled to claim expenses for the cost of a second home, even though the money went towards paying a business mortgage.

Mr Hemming said: You have to look at whether it is a good deal for the taxpayer. Did it cost the taxpayer more than would otherwise have been the case? Look at how my expenses compared to other MPs in Birmingham.”

He highlighted official Commons figures which showed he claimed £59,601 between becoming an MP in 2005 and last year – less than any other Birmingham MP.

Mr Hemming said on his blog in 2009: “I had a mortgage on another property in Birmingham at the time which needed payment and I knew I faced a reducing income because of the time I spent on parliamentary business.”