Millionaire MP John Hemming is subsidising his work as an MP by £30,000 a year, he has revealed.

The MP said he was helping to fund support for constituents from his own pocket as he defended a controversial expenses claim.

Mr Hemming (Lib Dem Yardley) 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 has provided examples of ways the money was used to help his constituents and issued a statement defending “indirect use of Additional Costs Allowance to support casework and constituency work”.

But Commons rules, in force until Additional Costs Allowance was abolished last year, state that the allowance is paid “to reimburse members for necessary costs incurred when staying overnight away from their main home for the purpose of performing Parliamentary duties.” It is not supposed to be claimed for any other reason.

Mr Hemming said he was now subsidising his work by about £30,000 a year from his own money, following reforms to Commons expenses rules.

The family law campaigner used some of the money on paying for legal advice to people facing family court action.

However before commons expenses rules changed, he funded this advice indirectly through his second home allowance, he admitted.

Cash from the mortgage indirectly helped Andrew France, from Sheldon, who was wrongly convicted of rape. He was finally freed in January after four years in jail – in which he missed the birth of his daughter - after the Court of Appeal ruled he was innocent.

He then faced separate family court proceedings, in which he received legal advice funded by Mr Hemming.

Mr France, a former housing official aged 47, said: “The work done by the advisors is very important and that extra support was essential to me as part of my appeal.”

The MP also highlighted the case of a woman from Acock’s Green who cannot be named, who fought attempts to take her baby away from her with support from an advisor known as a Mackenzie Friend, funded by Mr Hemming.

She said: “Without the help from my Mackenzie Friend, I would not have been allowed to take my baby home. The advice from John Hemming’s office is invaluable.”

And the MP highlighted the case of Fran Lyon, a resident in Yardley for a short period before she emigrated to Sweden to escape threats to remove her baby at birth. She had her baby in January 2008 and lives with her daughter in Sweden.

She said “I believe that the work John does, far above and beyond what his role as an MP requires him to do, more than justifies the way he has organised his finances.”

Ms Lyon highlighted Mr Hemming’s campaigning work to support people he argues are victims of a flawed family law system, saying: “Without his and his team’s advice and counsel I would not have had either the knowledge nor the strength to fight the system as I did: likely as not the happy, healthy home and future I have with my daughter would not have existed.”

The quotes were provided to the media with their permission by Mr Hemming’s office.

Mr Hemming no longer claims living expenses, but uses his own resources to subsidise his work.

He said: “I knew when I became an MP that my income was going to reduce, but I wished to subsidise constituency activity. I therefore, arranged my finances to enable me to best serve my constituents.”

He took out a £200,000 mortgage on a flat in Covent Garden, London – subsidised by the taxpayer – and used the money to repay a loan on offices housing his private business in Alcester Road, Moseley.

Like all MPs outside London, Mr Hemming was entitled to claim back the interest on a mortgage for a second home and received £825 a month. However, he has admitted that he did not need a subsidy in order to pay for the flat, which he already owned.