David Cameron today claimed that "secret corporate lobbying" was undermining public confidence in the political system.
In a speech at the University of East London, which he also used to attack Gordon Brown personally over his handling of the MPs' expenses controversy, the Conservative leader said he would force ex-ministers to wait two years before they are allowed to take a job lobbying government.
Cameron said lobbying was an issue that "has tainted our politics for too long".
He went on: "We all know how it works. The lunches, the hospitality, the quiet word in your ear, the ex-ministers and ex-advisers for hire, helping big business find the right way to get its way. In this party, we believe in competition, not cronyism.
"So we must be the party that sorts all this out. Today it is a £2bn industry that has a huge presence in parliament. The Hansard Society has estimated that some MPs are approached over 100 times a week by lobbyists.
"I believe that secret corporate lobbying, like the expenses scandal, goes to the heart of why people are so fed up with politics. It arouses people's worst fears and suspicions about how our political system works."
Under the current rules ex-ministers have to wait a year after they leave office before they can take a job lobbying government. Cameron said he would double this quarantine period and force ex-ministers to wait two years.
Ex-ministers also have to seek the advice of the advisory committee on business appointments if they want to take a private sector job in the first two years after they leave office.
Cameron said he would make rulings from the committee binding, not advisory, as they are now. He also said that ex-ministers who defied the committee would lose part of their ministerial pension.
