Mr Harvey, 37-year-old member for Devon North, had been seen as a strong contender, but polls indicated he is well behind Mr Campbell and Charles Kennedy, the front-runner.
Since Mr Ashdown stunned Westminster earlier this year with his decision to step down in June, a wide range of possible contenders has emerged. No MP is officially allowed to declare his or her candidacy until after the European elections, but supporters of Simon Hughes, Jackie Ballard, David Rendel and Don Foster, as well as those of Mr Harvey, Mr Kennedy and Mr Campbell, have all been lobbying.
Such a large field was unsustainable, Mr Harvey said yesterday. "There's a danger that we could end up looking ridiculous. Ming [Campbell] and I look at things in a similar way. This isn't an ego trip and I would be prepared to lend support to others," he told BBC Radio 4's The World at One.
Mr Campbell, 57, has not yet declared publicly his intention to stand, but as the Liberal Democrats' foreign affairs spokesman, he is widely seen as having had a "good war" with his Commons and media performances commenting on Kosovo in recent weeks.Reuse content