Mr Turner is stepping down at the end of the year after four years as director general about which he has said: "Je ne regrette rien."

Roger Lyons, general secretary of the Manufacturing, Science and Finance Union, says the positive industrial relations environment built up in the UK in recent years could be destroyed if an "anti-union fanatic" is appointed.

He said an "even harder line on employment rights" than has been taken up to now could upset the "delicate balance" that has evolved.

Roger Lyons: "No hardliners"

Under Adair Turner's stewardship, the CBI has been seen by the unions as being more approachable, and the MSF says it applauds the pressure the CBI has put on the government to water down European social directives.

When the name of the new director general is announced on Tuesday, the result will be known of months spent looking for the right candidate.

The rewards of the job are pretty good - a £200,000 package for running a staff of 230 and managing a £17m budget.

It is certainly a post with some clout. A survey of the most powerful people in the UK put Adair Turner at number 93, just behind the Pope.

What the job involves is formulating policy on behalf of the 250,000 public and private companies and 150 trade associations which belong to the CBI.

That policy must then be communicated to financial leaders, the UK and foreign governments, the European Commission and, of course, the media.

Turner: "Je ne regrette rien"

When Mr Turner announced he was stepping down, Michael Harrison, business editor of the Independent, said: "Turner's time at the CBI has broadly been judged a success.

"He is seen as being close to New Labour - he's not called Red Adair for nothing.

"Clive Thompson's appointment as president has acted as a foil to that - he's much more sceptical about Labour and things like trade union reform."

The new director general will have to work closely with Sir Clive, who became president 15 months ago.

Perhaps the biggest challenge will be in pushing forward the CBI's pro-euro policy. It is keen to see the UK adopt the currency but has had to work hard to get its point across.

One of the other main tasks facing the new chief will be steering an astute course between the political parties in the run-up to the next general election. It is here that diplomatic skills will be at a premium.

Under Adair Turner, the CBI switched smoothly after 18 years of Conservative rule in the UK to a good working relationship with the Labour government.

Track record

Adair Turner was born in 1955 and achieved first-class degrees in history and economics at Gonville and Caius, Cambridge.

From chairman of the Cambridge University Conservative Association in 1977, he joined the fledgling SDP in 1981.

He has declined to be a member of any party since the mid-1980s, saying he does not like the "tribal discipline".

He joined BP in 1979, moving rapidly to Chase Manhattan Bank before a long spell with management consultants McKinsey & Co. until he joined the CBI in 1995.

After leaving the CBI, he will be visiting professor at the London School of Economics.