Media playback is unsupported on your device Media caption Nick Clegg: "We must ensure we have the right processes and support structures in place"

The Liberal Democrats "let people down" by not dealing with claims made against the party's ex-chief executive Lord Rennard, Nick Clegg has said.

The leader told party delegates that allegations of inappropriate behaviour towards women would be "investigated thoroughly and independently".

Lord Rennard has denied the claims.

Mr Clegg said women who made complaints were not properly dealt with in the past and it was up to the party to make sure support structures were in place.

In his speech, on International Women's Day, the deputy prime minister told delegates gathering at the party's spring conference in Brighton: "When concerns were brought to the attention of members of my team, we acted to address them.

"But this should not have just been the responsibility of a few individuals acting with the best of intentions.

"It must be the responsibility of the party as a whole to make sure we have the processes and support structures in place now and in the future.

"We didn't, and as a result we let people down. Liberal Democrats, that is not acceptable to me."

The spring conference comes at a turbulent time for the Lib Dems and its president Tim Farron earlier said the party was in a "critical state" and its survival was not guaranteed.

Mr Farron, in an interview with The House Magazine, likened the party to a "cockroach" for its ability to survive, but said this should not be taken for granted.

Meanwhile, former Lib Dem cabinet minister Chris Huhne and his ex-wife Vicky Pryce are to be sentenced on Monday for perverting the course of justice.

Senior figures in the party are facing questions about when they knew of allegations that Pryce had taken speeding points on her husband's behalf.

'No excuse'

Meanwhile, the party has appointed businesswoman Helena Morrissey to head an independent inquiry into how it handled harassment complaints in the past.

Media playback is unsupported on your device Media caption Jo Swinson: "When a friend, Alison Smith, told me she had experienced unwanted advances, I was shocked"

Ms Morrissey, the chief executive of Newton Investment Management, will look at the party's culture and processes, its attitude towards women and the employment relationship between staff, elected officials and volunteers.

It is one of two investigations triggered by the allegations of inappropriate behaviour by Lord Rennard.

Addressing the conference, equalities minister Jo Swinson gave delegates details of how she handled the claims when they were first made.

She said "a number of women" had confided in her about alleged incidents several years ago with a "shared objective" of stopping the behaviour.

"Of course, I did not name names when I spoke to people in the leader's office about these claims," she added.

'Stunning victory'

In his speech, Mr Clegg described the Lib Dems as "a party that cherishes equality and women's rights" adding that, as such, it had "no excuse for failing to live up to the highest standards in the treatment of women".

The party leader said he had entered politics because he believed in "empowerment; freedom; dignity".

"I believe that, where an individual feels that they have been badly treated, or that power has been abused, they must have confidence that those concerns will be properly addressed," he added.

The Lib Dems tasted victory in the Eastleigh by-election last week when they held Chris Huhne's former seat but with a reduced share of the vote, ahead of the UK Independence Party.

Mr Clegg said Lib Dem candidate Mike Thornton had pulled off a "stunning victory" which had been secured "against the odds".

Addressing delegates, Baroness Shirley Williams praised Huhne's record as a constituency MP and "brilliant" minister.

On the Huhne and Pryce case she said: "We can only say of them that this is a tragedy that sometimes overcomes people not least those in public life."