Steve Baker told new MPs they would need “supportive, friendly colleagues who rely on one another”

New Conservative MPs have rushed to sign up with the party’s hardline group of Eurosceptics, casting doubt on claims that the size of Boris Johnson’s general election victory will allow him to ignore them.

Newly elected Tories outnumbered their experienced colleagues at the first meeting of the European Research Group (ERG) since last Thursday’s vote, its chairman said.

The new MPs included Joy Morrissey, who defeated Dominic Grieve, the pro-EU Tory rebel who stood as an independent in Beaconsfield, Buckinghamshire.

The ERG, formerly led by Jacob Rees-Mogg, was a thorn in Theresa May’s side as she repeatedly tried to get her Brexit deal through parliament. Some of its members, dubbed the Spartans, repeatedly held out against Mrs May, voting against her bill three