If MPs want to reform their working hours then they must make the effort to vote for it next Tuesday, Robin Cook has said.

The Commons leader was speaking after revealing there is a "narrow majority" for change among MPs.

But his appeal for modernising MPs to make the effort to vote follows a defeat last May on plans to reform the system of appointments to select committees.

In a free vote it was rejected by the narrow margin of 209 votes to 195.

Cook will be hoping to avoid a further rejection of plans to overhaul the Commons' arcane procedures next week, when MPs decide if they want to end the tradition of late night sittings.

The government has already conducted a survey of MPs views on the proposed reform, and in the Commons on Tuesday Cook revealed that around 550 of the 659 MPs had responded.

"I can say to the House there is a narrow majority in favour of change. Whether that narrow majority succeeds on Tuesday will entirely depend on whether those who support change turn up to vote for change," he said.

The exact figures are being revealed to a private meeting of the Modernisation Committee tomorrow, where Cook will set out the government's official response to the plans.

The reforms include:

• Beginning sittings on Tuesday, Wednesday and Thursday at 11.30am for oral questions.

• Completing main business on Tuesdays and Wednesdays at 7.00pm while on Thursdays main business would end at 6.00pm so MPs could travel that evening to their constituencies.

• Friday's would be set aside for constituency work, with the practice of government motions on the adjournment on Fridays being discontinued.