Research by the Royal United Services Institute (RUSI) found that the British Army and its allies were particularly deficient in artillery and ammunition, the BBC reports, adding that Britain's army was in dire need of "rejuvenation".

This comes at a time when Britain's armed forces have contracted in size nine years in a row, along with claims from House of Commons spending watchdog the Public Accounts Committee that the U.K.'s Ministry of Defence has a funding black hole of at least 7 billion pounds in its 10-year plan to equip Britain's armed forces

The report also noted such a conflict was "highly unlikely", though British forces would find themselves outgunned and outranged by Russian artillery, which reportedly destroyed two Ukrainian battalions within minutes in 2014.

An ongoing insurgency war in eastern Ukraine since 2014, along with Russian's annexation of the Crimea in the same year, led to the formation of NATO's Enhanced Forward Presence (eFP) Battlegroups in all three Baltic States, plus Poland. These became a reality in 2017, with Estonia's eFP being British-led and based at Tapa, east of Tallinn.

Several hundred British troops are in Tapa at any one time; units work on a rotational basis with a core regiment – at present the Queen's Royal Hussars – anchoring, and have been joined by personnel from other NATO allies including France, Belgium and Denmark.

The U.K.'s RAF also took on NATO Baltic air policing duties earlier on in the year; based at Ämari, west of Tallinn, the RAF's latest sting ended in summer, to be replaced by planes from the Czech Republic's air force.

For it's part, the MoD said that Britain works closely with NATO, noting that: "As the largest NATO defence spender in Europe, the U.K.'s armed forces are well equipped to take a leading role in countering threats and ensuring the safety and security of British people at home and abroad."

The report comes at a time when NATO has faced comments from France's president, Emmanuel Macron, who referred to the alliance as "brain dead", following the withdrawal of U.S. troops from northern Syria, ordered by President Donald Trump in mid-October.

Another NATO member, Turkey, has said that it opposes contributing to Baltic security unless more aid is given in its struggle with Kurdish forces in northern Syria.

According to the New York Times, U.S. troops are reengaging in counter-terrorism missions in northern Syria, however.

Last week, interior minister Mart Helme caused a media storm in Estonia after remarks made to Finnish daily Iltalehti where he said that Estonia, the other two Baltic States, and Finland, were in need of a "plan B" as an alternative to NATO defensive postures. Helme says his comments were misinterpreted.