William Cash, the hardline Eurosceptic Tory MP, has been appointed to the opposition front bench by the new party leader, Iain Duncan Smith.
Mr Cash – the Stafford MP described by the defeated candidate, Kenneth Clarke, as the most Europhobic politician in the House of Commons – will become the shadow Attorney General.
The surprise appointment will be seized on by moderate Conservatives as further evidence of the party being driven to the right by Mr Duncan Smith.
Mr Cash led the internal Conservative opposition to John Major's support for the Maastricht Treaty, tabling 240 amendments to the Maastricht Bill and voting against it 47 times. He also played a leading role in the European Foundation, bankrolled by the late Sir James Goldsmith, which opposed moves towards closer integration with Brussels.
Among his backbench allies in the guerrilla war against the Major Government's European policies was Mr Duncan Smith, who was then a newly-elected MP.
While many of Mr Cash's band of rebels have lost their seats, he has never wavered in his anti-federalist campaign. He recently responded to Mr Clarke's comments by asking: "What is 'Europhobic', extremist or disloyal about honestly debating such a vital matter?"
Some political commentators had assumed that Mr Cash would not be offered a Cabinet post in the reshuffle in an attempt to appease those party members known to be concerned at his views.
Duncan Smith aides insist his frontbench team is drawn from all sections of the party. But Clarke allies have been alarmed by rightwingers being appointed to the Shadow Cabinet's four most senior posts – Michael Howard (shadow Chancellor), Michael Ancram (shadow Foreign Secretary), Oliver Letwin (shadow Home Secretary) and David Davis (party chairman).
Mr Duncan Smith will also announce today that Eric Forth, the maverick libertarian former minister, will become shadow Leader of the House.
In other new appointments, Ann Winterton, the independent-minded MP for Congleton, will become an agriculture spokeswoman, and James Clappison, a Clarke supporter, is to become the Conservative spokesman on employment.