LONDON, August 3, 2008 (AFP) - Two successive defeats against South Africa and a run of poor form persuaded Michael Vaughan to quit as England captain Sunday.

Vaughan, 33, was England's most successful Test captain, leading the team to 26 wins in 51 Tests, including the Ashes triumph against Australia in 2005.

But he scored only 40 runs in five innings in the first three Tests against South Africa.

When the tourists won the third Test to take a winning 2-0 lead in the series, Vaughan decided it was time to go.

It was also announced that Paul Collingwood had resigned as England one-day captain. A new captain for both forms of the game will be announced Monday.

Vaughan will take a three-week break from cricket and is not available for the final Test at the Oval starting Thursday. But he said he wanted to continue playing for Yorkshire and England.

Ironically it was against South Africa five years ago that Vaughan ascended to the captaincy when Nasser Hussain resigned, also after a poor performance in Birmingham.

Vaughan and former coach Duncan Fletcher built up a formidable record, taking England to second place on the international Test rankings.

An elegant top order batsman, Vaughan had an ongoing battle against knee injuries which prevented him from leading England on the return Ashes tour in 2006/07.

Under stand-in captain Andrew Strauss, England lost all five Tests and the Ashes they had won in such thrilling fashion 18 months before.

He returned to the team against the West Indies last year and made a century against the West Indies at Headingley, Leeds, his home ground.

England suffered a rare home series defeat against India last year and lost against Sri Lanka on their 2007/08 tour.

Although they won away and at home against New Zealand, Vaughan admitted after the defeat against South Africa at Edgbaston Saturday: 'We've lost to the top bracket teams.'

At his after-match conference Vaughan said he would 'let the dust settle' before thinking of his future but less than 18 hours later he resigned.

'This decision has been something that has crossed my mind for some time,' he said.

'I had every ambition to lead the England team to the next Ashes Series but as England captain I feel I've run out of steam. I believe that the best thing for the team is to embark on a new direction under a new captain.'

'I also believe the best thing for me is to try and get back to being the best batsman I can be. I'll still have all the experience and knowledge to pass on and I hope to be a valuable player for both my county and the England team.'

Hugh Morris, managing director of England cricket, said Vaughan had always led from the front 'with an unprecedented level of professionalism, integrity and honesty every step of the way.'

'As a batsmen he has been one of the finest cricketers this country has seen and he took the England captaincy to new heights since assuming the role in 2003.'

South African captain Graeme Smith said he was shocked by Vaughan's decision. 'I have the highest regard for him as a person, sportsman and leader. It is a great loss for world cricket.'

South Africa announced Sunday that fast bowler Dale Steyn, who missed the Edgbaston Test because of a broken left thumb, would not be considered for the final Test. He is expected to be fit for a one-day series which follows the Tests.