David Cameron: 'We need to see the minutes of meetings, the emails...'
The "scandals" besetting Labour are "worse" than those which afflicted the Conservative government of the mid-1990s, David Cameron has said.
He called for a full government inquiry into the apparent willingness of Geoff Hoon, Stephen Byers and Patricia Hewitt to help a lobbying firm for cash.
Labour has suspended the three ex-ministers from the parliamentary party after they were secretly filmed.
The trio, who all deny wrongdoing, face possible parliamentary investigations.
Parliament's standards commissioner has been asked to look at complaints against Mr Hoon and Ms Hewitt while a source told the BBC that the Commons Standards Committee had approved Mr Byers' own request for an inquiry into his actions.
Gordon Brown has ruled out a government inquiry into the former ministers' alleged links with serving ministers after they were filmed for The Times newspaper and the Channel 4 show Dispatches in discussions with a fictional lobbying company.
But the three ex-ministers have been rounded on by Labour colleagues, Justice Secretary Jack Straw saying there was widespread "anger and incredulity" in the party at their actions.
And, speaking at his monthly press conference, the Conservative leader said the revelations would make people think all MPs were "sleazy pigs".
'Like a rash'
"Anyone who watched the Dispatches programme last night could not help but be, frankly, disgusted by what they saw," Mr Cameron said.
He added: "We need a proper [government] inquiry into all of this.
"The fact is the last government ended with scandals like this and the current government is ending with scandals that are, frankly, worse."
He added that lobbyists would be "all over MPs like a rash" in the next Parliament and there had to be safeguards.
The name of Parliament was being "dragged through the mud", he said, promising that a Conservative government would forbid former ministers from working for lobbying firms for two years after leaving office - double the current one year.
Their activities would also be legally bound by official guidelines for 10 years, he said.
Three other politicians were featured in the Dispatches programme - Labour MP Margaret Moran, Labour's Baroness Morgan and Conservative MP John Butterfill.
It is understood that Mr Butterfill - who was recorded saying he was likely to be given a peerage after leaving the Commons at the next election - has referred himself to the standards commissioner.
Sitting MPs are not banned from working for corporate clients but the practice is controversial
They must declare any payment in the register of members' interests
Any paid work taken by an ex-minister within two years of leaving office must be cleared by a panel - the Advisory Committee on Business Appointments
They are not allowed to table amendments or vote on bills in exchange for payment
They are normally banned for 12 months from becoming lobbyists in their specialist fields
Labour, the Tories and the Lib Dems all say they want the rules tightened to prevent ex-ministers exploiting their contacts for private gain
Mr Cameron said the peerage was "not going to happen", but there was no point withdrawing the Conservative whip in Parliament just two weeks before a general election is expected to be called, as this would not be the "most heinous" punishment.
For Labour, Business Secretary Lord Mandelson told the BBC it was "very convenient" for Mr Cameron to make such an argument.
Asked about the Conservative leader's criticisms, he said that "people in glass houses should not throw stones".
He added: "Overwhelmingly... politicians are committed to public service - what they can give to the public, not what they can take away."
Lib Dem leader Nick Clegg said Westminster was "sinking into corruption and hypocrisy", accusing the Conservatives of blocking reforms of lobbyists proposed by his party in 2006.
Plaid Cymru leader Elfyn Llwyd said Labour should be "ashamed" of the current state of affairs as they had had "more than enough opportunities" to regulate lobbying activities in Parliament.
And chairman of the committee on standards in public life, Sir Christopher Kelly, said he had been "greatly saddened" by the Dispatches programme and "the further damage that will do to people's perception of members of Parliament".
Under Commons rules MPs can work for companies, but must declare payments and may not lobby ministers directly.
Mr Byers, a former transport secretary, was filmed by Dispatches saying he was like a "cab for hire" who would work for up to £5,000 a day and claimed to have saved millions of pounds for National Express, which wanted to get out of its East Coast mainline franchise.
Transport Secretary Lord Adonis told peers on Monday there was "no truth" in the claims, dismissing them as "pure fantasy".
Mr Byers also said he had spoken to Lord Mandelson about getting food labelling proposals delayed, on behalf of supermarket Tesco.
Lord Mandelson, Tesco and National Express denied the claims - and Mr Byers said later he overstated his case and had never lobbied ministers.
Former Defence Secretary Mr Hoon was filmed saying he wanted to make use of his international knowledge and contacts in a way that "makes money" and that he charged £3,000 a day.
Following the reports, Mr Hoon said he would not lobby government or "attempt to sell confidential or privileged information arising from my time in government".
Ms Hewitt, a former health secretary, said she "completely rejected" the suggestion she helped obtain a key seat on a government advisory group for a client paying her £3,000 a day.
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