Keir Starmer leads calls for immediate general election
Watch: 'What a mess' - Sir Keir on Tory party leadership
Labour leader Sir Keir Starmer has called for an immediate general election following the resignation of the prime minister.  
Sir Keir said the country "cannot have another experiment at the top of the Tory party".
Liz Truss resigned as prime minister after just 45 days in the job, claiming she "cannot deliver the mandate on which I was elected".
A new prime minister is expected to be announced by 28 October. 
It will be the second Conservative Party leadership election this year.
Liberal Democrats, the SNP. Plaid Cymru and the Green Party have also been calling for an immediate general election.
Scotland's first minister has said a UK general election is a "democratic imperative" following the resignation the prime minister.
"This is an almighty mess, and it is people the length and breadth of the UK who are paying the price of this," she told the BBC
"Fundamentally the UK now needs to have a democratic choice over its next prime minister."
Sturgeon says the resignation of Liz Truss after 45 days is "beyond hyperbole and parody"
Liberal Democrat leader Ed Davey said: "We do not need another Conservative prime minister lurching from crisis to crisis, we need a general election.
"It is time for Conservative MPs to do their patriotic duty, put the country first and give the people a say."
He later told BBC Breakfast that no candidate could provide stability because the party is "so divided".
"The shambolic nature of the modern Conservative Party doesn't give me any faith in them," he said.
Sir Ed Davey criticises the records of Liz Truss and Boris Johnson as PMs as Conservatives look for a new leader.
xt general election is not due to take place until at least 2024, after the Conservatives won a landslide majority in the last one in 2019.
Ms Truss was elected by the Tory membership in September, but she lost authority after a series of U-turns.
In a brief speech outside Downing Street, Ms Truss said the Conservative Party had elected her on a mandate to cut taxes and boost economic growth.
She will become the shortest-serving PM in British history when she stands down.
Leading pollster Professor Sir John Curtice said whoever leads the Conservative party next should "enjoy the next 18 months to two years, because that will probably be their tenure".
"Parties and governments who preside over a fiscal crisis have nearly always struggled at the ballot box at the next election," Sir John said.
An Opinium poll this week projected a 1997-style landslide for Labour, with the party winning 411 seats. 
me poll, conducted for the TUC interviewing more than 10,000 adults, predicted the Conservatives would be reduced from 356 MPs to 137.
Sir Keir said: "This is not just a soap opera at the top of the Tory party - it's doing huge damage to the reputation of our country.
"We need a general election so the public can have their say on this utter chaos.
"There's a manifesto that is going to be ready whenever an election is called," Sir Keir told the BBC's Newscast podcast.
"I've had a team working on that. I've had a team working on general election preparedness. We've moved our teams on to a general election footing. 
"We're very, very prepared should there be a general election."
In his speech to the TUC conference on Thursday, Sir Keir said Labour had a long-term plan to "deliver cheaper bills and higher living standards for working people, growth and jobs in every part of our country". 
He outlined some of the policies he announced at Labour's annual conference last month, including those in its "green prosperity plan"
udes pledges to create a publicly-owned renewable energy firm, achieve carbon-free electricity by 2030, and insulate 19 million homes.