The Conservative Party has been hit by the resignation of Barry Legg, its chief executive.

The move, revealed on Wednesday evening, followed a decision by the party board to abolish his post of chief executive and "devolve responsibilities to other members of the management team".

The decision will be seen as a severe blow to the party leader, who had appeared determined to keep Legg in his post.

In a statement, Duncan Smith said he was "sorry" that the reorganisation had led to Legg's departure.

"I would like to thank Barry for his work over the past three months and am sorry that the reorganisation means that he will now be leaving. I would like to thank Barry for his work, both as my chief of staff and as CEO," he said.

Legg also expressed his regret at the move.

"I am sorry to be leaving so soon, and do so regretting that I have not been able to do more. I wish the party every success for the future."

In a snub to Duncan Smith, members of the party board decided to dispense with the post of chief executive officer after a "strategic review of the organisation and operation of Conservative Central Office".

Legg had come under increasing pressure to quit after just eight weeks in the job.

The former MP was appointed by Duncan Smith after he sacked reformer Mark MacGregor.

But members of the party's board were angered by the failure to consult them before making the decision to appoint Legg.

Several had threatened to quit over the affair.

Legg's past as a member of Westminster Council during the homes-for-votes scandal and his links as a company director for a firm found to have broken pension laws added to his difficulties.

During his time as an MP he was also a key rebel opposing the Maastricht Treaty.

Senior Conservative MPs had previously lobbied the party leader to sack Legg, but aides to Duncan Smith were said to have been angered that the row had resurfaced.

Others suggest the move, allied to Crispin Blunt's call for a leadership challenge, is part of an orchestrated attempt to undermine Duncan Smith.