JO Swinson has left the door open to challenging for the Liberal Democrat leadership once Sir Vince Cable steps down.

The current deputy leader, 38, also made clear the party had to change to attract new voters but that there was no need for a new centrist part as it already existed in the Lib Dems.

Asked if she was considering running for the leadership, the MP for East Dunbartonshire, who has hitherto suggested she is presently not interested in the leadership role, replied: "There's no vacancy at the moment. Vince has set out the things that he wants to do before he stands down." But then she added: "At the time that Vince does stand down, then absolutely I'll take a view at that point."

Ms Swinson, a former Business Minister in the Lib-Con Coalition government, also dismissed talk of a new centrist party, saying: "We've got the ingredients to be able to challenge the other parties, we've got the infrastructure of parties right across the country in terms of local associations, candidates, the whole idea of a centrist party gets talked about endlessly but doesn't really get off the ground.

"You don't need to set up a new party because the Liberal Democrats are here but we recognise that we have to change to make it easier for people that perhaps haven't looked at us before to look again at the Lib Dems."

Meanwhile, Sir Vince, 75, rejected claims he was "running out of road" as the Lib Dem leader as he again refused to set a firm resignation date; most pundits believe it will be next year.

Pressed on being at the helm at the 2022 General Election, he told the BBC’s Andrew Marr Show: "2022 is a long time off; it's improbable I will be leading us then."

In other conference developments the party:

*agreed to give migrant spouses an entitlement to benefits from their first day in the UK - without any form of means-testing;

*backed a new Geneva Convention to cover modern warfare and

*called for a £100 billion "citizens fund" to spread Britain's resources more evenly and formed over 10 years through a series of wealth tax reforms and via asset sales, including the taxpayer's stake in the Royal Bank of Scotland.