Maria Miller was clinging on to her cabinet post last night as senior colleagues depicted the culture secretary embroiled in an expenses row as the victim of “media antipathy” for her role in pushing through press regulation.

Iain Duncan Smith said the calls in the press for her resignation were in danger of becoming a “witch hunt” as he underlined his support even as a poll found that more than three quarters of voters thought Ms Miller should quit.

Her supporters argue that the culture secretary is under fire on two fronts. The newspaper industry is hostile to her as the minister dealing with the press in the wake of the Leveson inquiry into phone hacking, while many in her own party resent her for pushing through legislation on same sex marriage.

But parliament is now facing the prospect of a regulatory overhaul to finally deliver on David Cameron’s promise to “clean up Westminster” in the wake of the damaging expenses scandal of 2009.

Ms Miller’s detractors were still out in force on Sunday with Lord Tebbit, the former Conservative chairman, becoming the most senior party figure to call on her to resign. Sitting MPs meanwhile were also fuming that the 15-month investigation into her expenses, which concluded last week, had once more blown open the issue of MPs’ ethics.

The row has also reopened the issue of whether MPs should be allowed to police themselves after Sir Ian Kennedy, chairman of the Independent Parliamentary Standards Authority, said MPs should no longer be able to regulate their own affairs.

“MPs marking their own homework always ends in scandal,” Sir Ian told the Sunday Times. “It happened with expenses. It will happen with standards investigations too. Ipsa has shown than independent regulation of parliamentary behaviour can work.”

Under the current system any wrongdoing is investigated by an independent standards commissioner but an MP-run standards committee still makes the final judgment on any findings.

But this arrangement has come under heavy criticism in the past few days after the standards committee overruled the independent commissioner over Ms Miller’s expenses, ordering the MP to re-pay £5,800 in overclaimed expenses rather than the £45,000 recommended in the independent commissioner’s report.

Politicians on all sides accept that the status quo is no longer an option if they are to have any hope in regaining public trust. Mr Duncan Smith said the scandal was “eating away at the credibility of parliament” and that the system needed to be reviewed.

Angela Eagle, Labour’s shadow leader of the House of Commons, said the current set-up was no longer fit for purpose. “We need a system which commands public confidence, and what we have at the moment clearly doesn’t do that.”

Another Tory backbench MP said on Sunday that colleagues did not want to see further independent regulation of their behaviour, complaining that MPs on the standards committee had been wrongly criticised in the media. “They don’t close ranks. If they think someone has done wrong, they will say so.”

While parliamentary reform may be some time off, Conservative MPs are bracing themselves for political fallout of Ms Miller’s expenses row when it comes to the May local and European elections. The culture secretary’s job may be spared, but her colleagues are concerned voters will punish them in the polls.

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