By Laura Smith and agencies
Published July 3rd 2007 in Guardian Unlimited
In his first full statement to the Commons since becoming prime minister, he will reveal his intention to move power away from the government and towards parliament, with proposed measures including giving MPs the right to vote on issues of war and peace.
Mr Brown is expected to relinquish royal prerogatives traditionally exercised by the prime minister - such as the power to declare war without parliamentary approval - and to give MPs more powers.Under the proposals, MPs would be able to recall parliament in an emergency and scrutinise appointments to important public posts through US-style confirmation hearings.
Mr Brown is also said to favour a basic bill of rights for UK citizens, making clear their entitlements, and could also propose measures to give more power to the public, possibly through the creation of citizens' forums to express views on key local issues.
The new prime minister had been expected to set out his plans for constitutional reform yesterday, but the announcement was delayed in the aftermath of the attempted car bombings in London and Glasgow.
Mr Brown's spokesman said the decision to make the statement today was evidence of his determination that the business of government should carry on as normal.
Today, the cabinet broke with 44 years of tradition as the prime minister held the first of what will be regular Tuesday meetings.
He has moved the meeting from the Thursday slot it has occupied since 1963, saying he wanted a more consensual style of government with meetings regularly lasting for more than an hour.
In what will be seen as another attempt to distance himself from his predecessor, he said he would not run a "sofa-style" government.
Today's meeting - which lasted for an hour and 45 minutes - included an update from the home secretary, Jacqui Smith, on the weekend's attempted terror incidents.
It also featured a presentation from Mr Brown on the constitutional reform statement to MPs, which is expected to take place at around 3.30pm.
Prior to the PM's announcement, the Liberal Democrat leader, Sir Menzies Campbell, set out his own proposals for constitutional reform, including a written constitution drawn up by a constitutional convention involving political parties and members of the public.
He advocated replacing the House of Lords with a wholly or predominantly elected upper house, introducing a "fair" voting system for parliamentary elections - proportional representation - and bringing in limits on party funding and spending.
Sir Menzies urged the prime minister to carry out "bold and radical reform".
Mr Brown's new government was given a boost today when a new poll showed Labour had enjoyed a four-point increase in popularity since he became prime minister last week.
The survey, carried out by Populus for the Times, revealed the party was back above the Tories with a three-point lead - 37% compared to the Conservatives' 34%.
Mr Brown's personal rating was also up, with 77% describing him as strong - a 14-point increase on last month - and 57% saying he had what it took to be a good prime minister, a 16-point rise.
By contrast, 43% thought the Tory leader, David Cameron, was strong - up six points - while 37% said he had what it took to be a good prime minister, up four points.
Only 31% said they would prefer Mr Cameron to Mr Brown as prime minister, with 52% saying they would not.