Liz Truss attended a birthday celebration for a fellow MP two days before a positive Covid test forced her to cancel a key trip to Ukraine to defuse international tensions, it has emerged.

The South West Norfolk MP is reported to have held a belated 50th birthday event for Suffolk Coastal MP and work and pensions secretary Thérèse Coffey at her country residence, Chevening, on Saturday, January 29.

According to LBC, the foreign secretary attended the event alongside several special advisers and former special advisers.

On Monday, January 31, she cancelled her trip to Ukraine after testing positive for Covid-19, announcing she was self-isolating at home.

She had been due to travel to Ukraine with Boris Johnson in a show of support for the country, which faces the threat of invasion from neighbouring Russia.

The birthday celebration did not break any rules, and the MP's office has said the event was a private dinner.

However, Ms Truss has faced criticism from a Conservative colleague and figures in her constituency.

They have questioned the wisdom of holding the event at a time when there was such scrutiny of politicians attending celebrations - amid revelations about lockdown parties in Downing Street - and of running the risk of catching Covid at such a diplomatically crucial moment.

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

Pallavi Devulapalli, a Downham Market GP and 2019 Green Party parliamentary candidate, said: "Nobody would begrudge someone a birthday party, but when one is the foreign secretary and an important ally is facing a threat across its border, it makes me uneasy that a birthday party was given priority."

Eastern Daily Press: Pallavi Devulapalli will be travelling to Glasgow to take part in climate ralliesPallavi Devulapalli will be travelling to Glasgow to take part in climate rallies (Image: Archant)

She added: "It does feel as if all that our elected people in government do is party."

Josie Ratcliffe, Liberal Democrat parliamentary spokesperson for South West Norfolk, who also stood in the 2019 election, said: "It is disappointing that Liz Truss prioritised attending a party over the importance of her role as foreign secretary.

Eastern Daily Press: Josie Ratcliffe, borough councillor for Downham Market East. Picture: Liberal Democrats.Josie Ratcliffe, borough councillor for Downham Market East. Picture: Liberal Democrats. (Image: LIberal Democrats)

"Although we're returning to socialising, Covid infection rates remain high and there are still rules for self-isolating and travel.

"But instead of being cautious before her meeting with Ukraine's president, and while Russian troops were building up at their border, Ms Truss chose to host a party.

"She could have shown leadership in delaying it until after this important trip, but instead she took a risk and consequently failed to fulfil her responsibilities."

Ms Truss is now due to travel to Moscow later this week for discussions with her counterpart Sergei Lavrov.

A spokesman at Ms Truss' office said: "The foreign secretary has been spearheading diplomatic and deterrence efforts on Ukraine.

"She has taken a tough stance on Russia and helped lead a coordinated international response.

"She speaks regularly to allied counterparts, last weekend announced a strict new sanctions regime against Russia and is flying to Moscow this week to urge the Kremlin to choose diplomacy over conflict.

"The event in question was a private dinner that took place on a Saturday evening, completely within the current government guidelines."

Ms Coffey has also been contacted for comment.