London, Oct.4 : Peter Mandelson has described his return to the British Cabinet "great challenge and a great opportunity".
Speaking outside Downing Street, Mandelson said his comeback was "third time lucky", in apparent reference to his two previous spells as a Minister. He was forced out of Government under controversial circumstances in 1998 and 2001.
He added that while he and Gordon Brown had had their "ups and downs" in the past, they now "worked very well together".
"I've very much enjoyed my work in Europe, on trade and development issues. But the Prime Minister has asked me to come back," he said.
"Our economy, like every other, is facing a very big challenge. It's all hands on deck. I will be working with the rest of the Government as hard as I can to pull us through it.
"I'm very proud to have been invited to join the Government - it's not what I was seeking, and not what I was expecting - but I'm looking forward to working with my friends and colleagues... third time lucky."
He will leave his post as a European Trade Commissioner in Brussels.
He will be given a peerage and take up his old job as Secretary of State for Business as Prime Minister Brown reshapes his Government to reassure people he is tackling the international financial crisis.
John Hutton, the current Business Secretary will become Defence Secretary, a post he has long coveted, in one of a number of significant Cabinet moves.
Mandelson's appointment has been met with astonishment by left-wing Labour MPs. John McDonnell called it an "extraordinary step backwards," adding: "The whole Labour movement will be utterly perplexed at what the Prime Minister's motives are."
Peter Kilfoyle MP called the move "divisive", saying: "I believe that the recall of twice disgraced former MP Peter Mandelson is a thoroughly retrograde step which will do nothing to promote unity within the Labour Party."
Shadow Foreign Secretary William Hague said that the reshuffle was a "stunning failure of judgment" by Brown.
Business leaders, who have praised Mandelson's free trade credentials, have welcomed the appointment.
The reshuffle means Des Browne, the current Defence Secretary, is leaving the Government having turned down a new job overseeing Scotland, Northern Ireland and Wales.
To underline the government's economic credentials, the Prime Minister will also appoint a number of "big name business ambassadors" including Sir John Bond, the chairman of Vodafone.
Geoff Hoon, the Labour chief whip, will eventually replace Mandelson as Britain's commissioner in Brussels, though not until next year when a new commission is sworn in.
The Leader of the Lords, Baroness Ashton of Upholland, is to replace Mandelson in Brussels as an interim commissioner.