David Cameron was under pressure last night to disclose whether other members of the Shadow Cabinet failed to register with the Commons authorities donations to support their offices.

George Osborne, the Shadow Chancellor, was reported to the Parliamentary Commissioner for Standards and the Electoral Commission by Labour MPs who accused him of failing to declare fully donations of £500,000 to support his frontbench work.

The Conservative leader admitted that other members of the Shadow Cabinet might be in a similar position. At a press conference, Mr Cameron said that researchers were moved to frontbenchers’ Commons offices in 2006. Some have returned to party HQ; others still work at Westminster.

Shadow Cabinet members’ offices are privately funded by three routes, in addition to “Short money” — public funds for parties’ parliamentary work.

Rejecting suggestions that his Chief Whip had sought advice on the rules for declarations after the scandal last year over donations to the Labour Party, he said: “We have fairly regular meetings.All the time I am saying to my office, have we declared this, have we declared that?”

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