The UK Government was left in the dark while Russia annexed large parts of Ukraine because British diplomats can’t understand Russian, according to a scathing new report by MPs.

Language skills at the Foreign Office are said to have become so poor that officials were unable to adequately advise the Government on the unfolding annexation of the Crimean peninsula.

“British diplomacy towards Russia and elsewhere has suffered because of a loss of language skills, particularly in the Foreign Office,” Sir Tony Brenton, a former British ambassador to Moscow, told the House of Lords External Affairs Sub-Committee.

“There was quite a lot of complaint in Whitehall after the annexation of Crimea that the Foreign Office had not been able to give the sort of advice that was needed at the time. I think that is regrettable and it marks a change from when I was there.”

The Foreign and Commonwealth Office Building in London (MANDEL NGAN/AFP/Getty Images)

The revelations came to light in a report by Parliament’s Foreign Affairs Committee, which has been scrutinising the Foreign Office’s performance.

The committee's MPs found that only 27 per cent of Russian “speaker slots” at Britain’s foreign ministry were filled by someone who could speak the language to the specified level.

The figure across all languages was only 38 per cent, a fact the committee described as “alarming”.

The cross-party group of MPs found that cuts to the FCO’s budget meant the department was finding it difficult to retain the right level of expertise.

Further government cuts would “probably” mean a significant reduction in Britain’s world influence and a scaling back of its foreign policy ambitions, they concluded.

In pictures: Russian troops in Crimea as Ukraine crisis continues Show all 10 1 /10 In pictures: Russian troops in Crimea as Ukraine crisis continues In pictures: Russian troops in Crimea as Ukraine crisis continues Pro-Russian protests in Crimea Pro-Russian protesters, including one woman holding a sign that reads: 'The time has come to return my name! I am Russia. And not Ukraine!', hold up a giant Russian flag as they march in Simferopol, Ukraine, on 1 March. Sean Gallup/Getty Images In pictures: Russian troops in Crimea as Ukraine crisis continues Pro-Russian protests in Crimea Pro-Russian protesters marching in Simferopol, Ukraine, on 1 March. Sean Gallup/Getty Images In pictures: Russian troops in Crimea as Ukraine crisis continues Russian troops in Crimea A young man carrying flowers confronts heavily-armed soldiers displaying in a street in the city centre of Simferopol, Ukraine, on 1 March. Sean Gallup/Getty Images In pictures: Russian troops in Crimea as Ukraine crisis continues Russian troops enter Crimea Two young women sit in a shop as heavily-armed soldiers stand outside in Simferopol, Ukraine, on 1 March. Sean Gallup/Getty Images In pictures: Russian troops in Crimea as Ukraine crisis continues Pro-Russian protests in Crimea Pro-Russian protesters wave the orange and black colours of Russian military valour at an anti-American rally in Simferopol, Ukraine, on 1 March. Sean Gallup/Getty Images In pictures: Russian troops in Crimea as Ukraine crisis continues Pro-Europe protests continue in Kiev A man walks with an EU flag at the bridge overlooking Independence Square in central Kiev on 1 March LOUISA GOULIAMAKI/AFP/Getty Images In pictures: Russian troops in Crimea as Ukraine crisis continues Russian troops guard Crimean parliament Heavily-armed soldiers guard the Crimean parliament building shortly after taking up positions there on 1 March in Simferopol, Ukraine Sean Gallup/Getty Images In pictures: Russian troops in Crimea as Ukraine crisis continues Protests continue in Kiev A member of a so-called 'Maidan's self defence unit' looks at pictures of protesters who were killed during recent clashes, displayed in central Kiev on March 1 Bulent Kilic/AFP/Getty Images In pictures: Russian troops in Crimea as Ukraine crisis continues Russian troops in Crimea Women look on as troops guard the Crimean parliament building in Simferopol, Ukraine, on 1 March Sean Gallup/Getty Images In pictures: Russian troops in Crimea as Ukraine crisis continues Funerals continue in Kiev A woman holds a candle during the funerals of a man who was killed during the recent clashes with the riot police on Kiev's Independence square on 1 March. Bulent Kilic/AFP/Getty Images

“The cuts imposed on the FCO since 2010 have been severe and have gone beyond just trimming fat: capacity now appears to be being damaged,” the committee’s MPs wrote.

“If further cuts are imposed, the UK's diplomatic imprint and influence would probably reduce, and the Government would need to roll back some of its foreign policy objectives.”

The committee’s report also said there were serious shortages of capable Arabic speakers at the Foreign Office – despite a long history of instability in the region.