Eurosceptic Tory MPs have signed a letter calling on David Cameron to continue as prime minister - whatever the result of the EU referendum.
Eighty-four MPs - including prominent Brexit campaigners such as Boris Johnson and Michael Gove - have signed the letter which says Mr Cameron has a "mandate and duty" to continue.
But Iain Duncan Smith, who famously resigned as work and pensions secretary during the campaign, is a notable absentee from the list of Tories who have signed.
The letter was delivered to 10 Downing Street as counting got under way in the historic referendum.
Mr Cameron's future has been questioned during an often bitter campaign which has divided his own party.
Leave campaigners condemned the prime minister and chancellor's tactics, accusing them of "scaremongering”.
Some Tories were considering writing to the Graham Brady, the chairman of the 1922 Committee of backbenchers, calling for a vote of no confidence in the prime minister.
Among them was prominent Cameron critic Nadine Dorries, who told Peston on Sunday that the prime minister will be "toast within days" unless Remain win a significant victory.
Mr Cameron has already said he will stand down before 2020.