[2] Serving an annual average of 21 MPs[3][needs update] including cabinet members, the group's focus is the single issue of the UK's withdrawal from the European Union.

[6] Support for the group was boosted in 1995 after it published an anti-federalist pamphlet discussing Euroscepticism which included a foreword by Prime Minister John Major.

This created an opportunity for the ERG, an unincorporated association with no obligation to publish accounts, to fund researchers and establish a social media communications network at taxpayer's expense.

"[20] On 26 July 2018, the German public international broadcaster Deutsche Welle reported that "The European Research Group is a lobbying entity pushing for a no-nonsense, hard Brexit.

and "In February 2017, the group sent a letter to May setting out their hard-line Brexit demands: Britain should not only leave the EU but also the single market and customs union.

"[21] On 11 March 2019, the Constitution Unit in the Department of Political Science at University College London reported in Monitor 71 that "The Conservatives have their own party-within-a-party, in the strongly pro-Brexit European Research Group.

[80] OpenDemocracy's September 2017 report commenced:Taxpayers' money is being used to fund an influential group of hard-line pro-Brexit Conservative MPs who are increasingly operating as a "party-within-a-party".