In 1977 Prime Minister James Callaghan and Liberal leader David Steel struck a constitutional deal, by which the Labour government could survive a vote of no confidence and get its business through Parliament, while the Liberals gained access to the anterooms of power.

The Pact, a contemporaneous account of the hatching and workings of the 'Lib-Lab' deal of 1977-8, is an invaluable time-capsule of British politics but also a pointer to its future. Coalition government has oft been scorned in Britain, since - as Alistair Michie and Simon Hoggart note - the main parties regard their opponents chiefly as 'targets off which points may be scored'. But hung parliaments and inter-party deals, as revived in May of 2010, may be back to stay.

This new edition of The Pact, in memory of its co-author Simon Hoggart (1946-2014), includes new prefaces by David Steel, Roy Hattersley, and the journalist Stephen Bush.