Theresa May has held meetings with leading Tory Remainers, amid speculation about further defections.
Justine Greening and Phillip Lee say Mrs May has ignored requests from pro-EU Tory MPs in favour of Brexiteers.
The pair had separate meetings with the PM in Downing Street.
Meanwhile, one ex-Labour member of the new Independent Group of MPs has said it could help keep Mrs May in power on condition that she agreed to another EU referendum with Remain as an option.
However, the PM was focused on her own party on Thursday, as she met cabinet ministers David Gauke and Greg Clark.
The pair have warned of the dangers to business of leaving the EU without a formal deal, an option which Brexiteers in the European Research Group of Conservative MPs insist must be preserved as negotiating leverage in Brussels.
The government said on Thursday that talks would continue “urgently” at a technical level, following “productive” meetings involving Brexit Secretary Stephen Barclay, Attorney General Geoffrey Cox and the EU's chief negotiator Michel Barnier.
In the UK, ex-Labour MP Gavin Shuker told The Huffington Post members of the new Independent Group had first made the offer of a potential confidence and supply agreement – like the one the DUP has with the government – last month in a meeting with the PM's second-in-command…
