Twickenham MP Vince Cable’s determination to remain active in his constituency has seen him step down from his role as deputy leader of the Liberal Democrats.

The Business Secretary, who has been MP for Twickenham for 13 years, said the move would allow him to focus “wholeheartedly” on his new role in the coalition Government, while continuing to give his all as an MP.

Speaking to the Richmond and Twickenham Times, he said: “I have a very big department with major responsibilities and a large workload and I am determined to continue as an active constituency MP.

“I cannot reconcile these commitments with continuing a national party role.”

Dr Cable has stressed he will continue to work for the people of Twickenham, despite now managing a department with a budget of £6bn and 3,000 employees.

Speaking after being assigned the job of Business Secretary, he said: “I will have a heavy workload, but I am determined to continue as a good constituency MP.

“Since I am now Minister I have direct responsibility for some of the major employers and institutions in the constituency.”

The ballroom dancing fanatic gave up his role as deputy leader on Wednesday – a position he had held since 2006.

In a letter to Lib Dem leader Nick Clegg, Dr Cable said it had been “an honour” to serve as the deputy leader of the party.

He wrote: “However, in joining the Cabinet I have taken on many new challenges and responsibilities and it is right that I focus wholeheartedly on the job in hand.

“I wish my successor all the best in what is a rewarding and important role.”

He said he believed the Lib Dems had a “real opportunity to change Britain for the better”.

Dr Cable, a former chief economist for oil company Shell, retained his Twickenham seat after winning 32,483 votes in the general election on May 6 – 12,000 more than Twickenham Conservative candidate Deborah Thomas.

Mr Clegg paid tribute to Dr Cable and said he had been a “fantastic deputy leader” and he was looking forward to the two of them working together in the new Government.

A successor will be elected by the Lib Dem parliamentary party on June 9.