Liberal Democrat leader Tim Farron has warned that Britain's business heavyweights have until Christmas "to save the country and themselves" by abandoning their support for the Conservatives and rallying against an exit from the European single market.
Mr Farron said corporations could derail attempts by Prime Minister Theresa May to seek a "hard Brexit" by ditching the Tory Party in their droves and shifting their support to the Lib Dems.
Speaking to the Press Association, he said: "(Big corporates) have the ability to sit down with Theresa May and say 'The game's over. W e are dropping you because you have chosen to give in to a right-wing nationalist, protectionist bunch, which give you rounds of applause at your conference and some good headlines, but are damaging the long-term future of our country and indeed for the City.' I think that would be very powerful."
He said Lib Dem peer Baroness Susan Kramer had been meeting major financial institutions in the City, which were "terrified of Brexit" and do not want to leave the single market.
"Business is wise to be calm, to be patient and not to panic because that is how it normally is, but things are so urgent that a bit of constructive panic would be quite sensible," Mr Farron added.
"You could leave it six months and Article 50 would be triggered potentially and, depending on which lawyer you believe, that could mean it is too late, we have jumped out of the plane without a parachute. So I would argue they have got until Christmas to save themselves and the country."
The clarion call came as Mr Farron announced key members of the party's business advisory group, as he pushes the Liberal Democrats as the "free market, free trade, pro-business party".
Chaired by former business minister Jo Swinson, the group includes Dinesh Dhamija, the founder of eBookers; Richard Pym, chairman of Allied Irish Bank; Alex Depledge, founder of hassle.com; Richard Steer, chairman of Gleeds Worldwide; and Susan Tobbell, founder of petrol station retailer MRH (GB).
Julia Goldsworthy, ex-shadow chief secretary to the Treasury , will also chair a working group on the 21st century economy, while former business secretary Vince Cable will take charge of a business tax simplification group.
Mrs May dismantled her business advisory group last month, raising concerns that she may not consult the business community in the run-up to Britain's formal negotiations on Brexit.
Mr Farron said businesses were coming to the Lib Dems because they see a "determination to prevent the worst of Brexit - a 'hard Brexit' - that nobody voted for ".
The Liberal Democrats want to halt potential plans to pull the UK out of the single market by demanding that the Government puts its Brexit deal to the public vote in a second referendum.