Commons speaker in expenses storm

Critics insisted Michael Martin must hand over control of a review of MPs' allowances after fresh questions arose over those claimed by him and his wife, Mary.

The disclosure that his office deceived the public over Mrs Martin's taxpayer-funded taxi journeys caused his spokesman, Mike Granatt, to resign for "ethical reasons".

The Parliamentary Commissioner for Standards has been urged to investigate the revelation that Mrs Martin had not been accompanied on the trips by a Commons official, as had been briefed, but by her housekeeper. There is also concern over Mr Martin's use of the second home allowance after it emerged he has no mortgage on a property for which he has claimed more than £75,000 to maintain.

But anti-sleaze campaigner Martin Bell said Mr Martin was in fact being protected from MPs' criticism by the convention that they do not openly criticise the Commons Speaker.

"He is protected by a wall of silence, actually, because MPs can talk about anything they like, inside or outside the House, except their views about the Speaker," the former independent MP said. "They do not speak up and we know there is widespread disquiet on both sides of the House and no-one dare speak up."

He was joined by former sleaze watchdog Sir Alistair Graham in urging Mr Martin to pass responsibility for a review of MPs' expenses to an independent body.

"It's unfortunate and really does undermine the credibility of this review that he himself has become part of this story, although it's clear that he hasn't broken any rules," Sir Alistair said. "But it does suggest the rules are inappropriate and need radically reforming."

The TaxPayers' Alliance has written to the Parliamentary Commissioner for Standards, John Lyon, urging him to investigate Mrs Martin's taxi trips amid doubts that they were in fact used for official business related to the Speaker's office.

But senior Labour figures have come to the Speaker's defence. Former home secretary David Blunkett described a string of negative stories about Mr Martin as a "witch-hunt". Ex-foreign secretary Margaret Beckett said: "Clearly someone is out to get him. Whether any of it is valid, I can't judge."