Conservative rightwingers are planning to present Rishi Sunak with demands for tougher action on immigration and human rights law before the election if the prime minister’s manifesto promises on Tuesday fall flat.

Prominent party figures including Suella Braverman and Robert Jenrick are said by Tory insiders to be among those waiting to see how the manifesto is received by the public before they act.

.In the event Sunak’s launch fails to shift the dial on the Tories’ floundering election campaign, one option under discussion is a press conference next week to set out a series of alternative pledges.

They are hoping to capitalise on an already weakened Sunak who vowed to fight on until the last day of the campaign after a terrible weekend in which he was criticised for missing part of the D-day commemorations.

On the campaign trail in West Sussex on Monday, the prime minister said he believed he could still win back voters and he did not accept that the election result was a foregone conclusion