David Cameron has told his Shadow Cabinet members that they will be required to give up all outside interests by the end of the year. The Conservative leader published a list of payments to his senior colleagues yesterday, before new rules that require the disclosure come into force tomorrow.

Michael Gove, the Shadow Schools Secretary, tops the list of earners, disclosing that he works for “an hour or so” a week writing a column in The Times, for which he is paid £5,000 a month. Francis Maude, in charge of preparing for an incoming Conservative government, earns more than £6,000 a day for his work as an adviser to Barclays Bank.

Mr Cameron said that by the end of December almost all his Shadow ministers would be able to focus all their efforts on “setting out our credentials as an alternative government”.

Gordon Brown, meanwhile, faced fresh humiliation after he was forced to scrap a legally binding code of conduct for MPs when he bowed to pressure from his own sleaze watchdog and Michael Jack, the Clerk of the Commons, among others.

The Prime Minister had repeatedly boasted that he wanted to introduce a code, enshrined in law, “which sets out the responsibilities, the code of conduct for MPs”. However, Mr Jack, the Commons’ most senior official, protested that this would interfere with parliamentary privilege.

Government sources confirmed that the proposed code was being withdrawn, insisting that the financial elements of the existing code of conduct were already elsewhere in the Bill.

The Tories revealed their own concerns about the Bill, putting down “exploratory” amendments to scrap the three new offences of claiming falsely on expenses, promoting outside interests for money and failing to declare second jobs.

Alan Duncan, the Shadow Commons Leader, said that his party had particular concerns that the proposed law on expenses duplicated the Theft Act. Tory sources told The Times, however, that they would still support the laws banning the promotion of outside interests and failing to declare second jobs.

Sir Philip Mawer, Mr Brown’s adviser on ministerial interests, said that proposed disciplinary procedures for misbehaving MPs were “a recipe for delay, cost and confusion”. In evidence to the Committee on Standards in Public Life, he voiced concerns that the speed with which they were being hurried on to the statute book may result in a flawed reform.

Mr Cameron said yesterday that having a second job was not incompatible with being a good MP. “There are idle MPs with no outside interests and there are fantastic public servants that do have them,” he said. “My Shadow Cabinet have, however, recognised that we are in a particular period at the end of a five-year Parliament, where it does become necessary to demonstrate 100 per cent focus on Parliament, politics and setting out our credentials as an alternative government so they have decided that from the end of December they won’t have any outside interests.”

Reforms coming into force from tomorrow mean that all MPs will be obliged to list hours and details of pay for outside work. Previously, MPs have had to name their outside employers and directorships in the Register of Members’ Interests but have never had to reveal how long they spend on the work, and needed to give an indication of how much they were paid only if the job related to their work as an MP.

Some high-earning Tory frontbenchers, including William Hague, the Shadow Foreign Secretary, have already indicated that they are to give up outside roles. Mr Hague earned about £230,000 last year from after-dinner speeches, advice to private companies and writing books.

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