The new approach to politics trailed by Gordon Brown in his speech to the National Council for Voluntary Organisations will include policy advisory roles for opposition MPs, a move that has been broadly welcomed by the other major parties in Parliament.

However, Conservative Party chair Caroline Spelman lamented the failure of the prime minister to demonstrate “basic courtesy” by phoning David Cameron and informing the opposition leader of his plans to offer specific policy roles to Tory backbenchers Patrick Mercer and John Bercow.

“That would have lent a little bit more credence to the idea that this was a genuinely cross-party approach,” Spelman said.

But she said that the expertise that Bercow and Mercer had, in the respective areas of children with special needs and security, meant that both would prove “an asset”.

Highlighting David Cameron’s desire to avoid “opposition for opposition’s sake”, she said the Conservatives supported any genuine move towards more consensual politics.

Lib Dem Matthew Taylor, who will offer advice on the future of rural planning, said he had consulted his party leader, Sir Menzies Campbell, and declared that the initiative was “worth doing”.

“In terms of the politics, I don’t have a problem with it; I’ve worked for many years to get a more inclusive type of politics in this country,” remarked the Truro and St Austell MP.

“I could have turned this down, I could have said Gordon Brown happens to be a Labour politician, I happen to be a Liberal Democrat therefore I’m not willing to get engaged in actually solving the problems of affordable rural housing and bringing up incomes and business in these rural communities. If I’d done that, I’d have been rightly condemned by the people who are at the sharp end; the people who are finding that they can’t get an income to afford a home in their community”.

Justice secretary Jack Straw dismissed suggestions that the announcements were driven by political chicanery on the part of the prime minister, insisting “Gordon Brown is absolutely serious about this”.

“All three major parties have an interest in improving the way our politics is run, so that we reach out better, we have more people involved make use of their rights as citizens in an active and not just a passive way,” Straw said.