Members of the European Research Group include Suella Fernandes, Dominic Raab, above, its leader Steve Baker, below left, and Theresa Villiers, below right, who are having an increasing influence on the government

They are the most powerful opposition force in British politics, but even the denizens of Westminster would not recognise the group by its official name. They have more influence than Her Majesty’s official opposition, five times more MPs than the Lib Dems and a sense of discipline that puts the SNP to shame.

The most aggressive and successful political cadre in Britain today is run by a nucleus of Brexit-supporting Tory MPs from the traditional right who for more than a decade were derided by David Cameron.

Ministers say that the direction of government is being shaped by what happens on a private WhatsApp message group for 59 members of the European Research Group (ERG), a little-known organisation led by Steve Baker, the High Wycombe