Prime minister Liz Truss and chancellor Kwasi Kwarteng will meet the head of Britain’s independent fiscal watchdog today following a market meltdown triggered by the mini-budget.

Alisha Rahaman Sarkar www.independent.co.uk

In an unusual move, Ms Truss and chancellor Kwarteng will meet the chairman of the Office for Budget Responsibility (OBR) Richard Hughes to discuss the economic and fiscal developments.

Mr Kwarteng unveiled a string of tax cuts last week in a fiscal statement that was not accompanied by OBR forecasts. The forecaster said it had offered to prepare a draft for the new chancellor in time for the mini-budget but it was not taken up.

Now, a group of lawmakers have reportedly called for the forecast to be released immediately.

The chancellor has insisted that he is “sticking with” his mini-budget, despite it spooking markets and forcing an emergency Bank of England intervention.

Meanwhile, Tory MP Sir Charles Walker said the Conservative Party faces an existential threat after Labour surged to a 33-point lead in one poll.

He suggested the Conservatives would “cease to exist as a political party” if the 33-point lead is repeated at a general election.