Former Thatcher ally to be Cameron's trade adviser

David Cameron said Lord Brittan – who served as Home Secretary and Trade and Industry Secretary in Margaret Thatcher's government – had

"unrivalled experience" for the role.

The former Richmond, north Yorkshire, MP will, however, only remain in the post for six months before returning to investment bank UBS, where he is vice chairman.

The news comes amid Labour claims the Government is facing a "major embarrassment" because it has not yet appointed a trade Minister to promote UK interests overseas, with prominent business grandees supposedly shunning the job. Its last incumbent under Labour, the ex-Standard Chartered Bank chairman Lord Davies, is said to have declined an offer from Mr Cameron to stay on.

Mr Cameron said: "I am delighted that Lord Brittan will bring his unrivalled experience and know-how to what is one of the most important issues we face – to drive forward our ambitious trade agenda.

"As we come out of recession it is crucial that we demonstrate that the British economy is open for trade, open for investment and open for business. Crucial not just for our economic growth and the jobs it will create but also to help some of the poorest countries in the world develop too."

Lord Brittan, who formally takes up the role next month, said: "Removing trade barriers and stimulating investment is crucial for our national prosperity. To help work out how this can best be achieved, both nationally and internationally, is an immensely exciting challenge, I am honoured and delighted to be asked to take this on."

Lord Brittan resigned from the Thatcher government in 1986 after he was found to have leaked a damaging letter during Cabinet in-fighting over Westland.

He spent most of the 1990s serving on the European Commission, where one of his aides was Mr Clegg – now Liberal Democrat leader and Deputy Prime Minister.

Lord Brittan tried to convince Mr Clegg to become a Conservative instead of joining the Lib Dems but the euroscepticism of many Tories put the Sheffield Hallam MP off, and the two remain close friends.

One of the 70-year-old's main tasks will be to make progress with the Doha round of international trade talks.