LIZ Truss hosted a 50th birthday party for a Cabinet colleague at her grace and favour country mansion just two days before she was forced to cancel a foreign visit due to testing positive for Covid-19.

The bash was also just 48 hours before Sue Gray published an update on her report into rule-breaking gatherings on Downing Street, with one senior Tory colleague branding Truss “arrogant” and “stupid”.

LBC revealed that the Foreign Secretary invited Work and Pensions chief Therese Coffey over to Chevening – a 115-room country house she shares access to with Deputy Prime Minister Dominic Raab – on January 29.

Several special advisers and former aides also attended, with the report suggesting the group were “plotting” a potential leadership bid.

The National: Work and Pensions Secretary Therese CoffeyWork and Pensions Secretary Therese Coffey

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No rules were broken but two days later, on Monday January 31, Truss was forced to abandon plans to visit Ukraine, having contracted Covid-19. One other attendee at the bash is understood to have tested positive, though Coffee did not.

Gray’s report, also published on the Monday, condemned "failures of leadership and judgement" and excessive drinking at Number 10.

Reacting to the LBC report, one senior Tory said: "So arrogant, so tone-deaf, so stupid."

Asked about the Chevening bash, technology minister Chris Philp said: "I don't think we should begrudge Therese Coffey and Liz Truss a birthday dinner, to be honest, I'm sure we've all been to birthday dinners since the lockdown restrictions have been eased.”

Truss will travel to Moscow later this week for discussions with counterpart Sergei Lavrov.

The Foreign Secretary’s team declined to comment on the party.