A Russian fighter jet nearly shot down an RAF reconnaissance plane over the Black Sea last year, Western intelligence documents have revealed, in an incident which could have drawn the UK directly into the Ukraine war.
On September 29, an RAF RC-135 Rivet Joint surveillance aircraft was flying through international airspace close to the Russian-occupied Crimea peninsula when it was buzzed by a squadron of Moscow's Su-27 fighters.
At the time, British Defence Secretary Ben Wallace acknowledged the incident, telling Parliament that the Russian jets 'recklessly' came within 15ft of the RAF plane and one 'released a missile in the vicinity'.
Russia's defence minister Sergei Shoigu blamed a technical malfunction and Wallace, having spoken with other Russian defence officials, accepted the explanation and drew a line under the incident.
But leaked US military documents have now revealed that the missile launch came agonisingly close to striking the RAF aircraft in an incident that was described as 'a near-shoot down of UK RJ (Rivet Joint)'.
Had a Russian missile blown Rivet Joint out of the sky over the Black Sea, the UK and its Nato allies may have been compelled to war.
According to Article 5 of the founding treaty of Nato, member nations agree that an armed attack against one or more of them 'shall be considered an attack against them all'.
If such an attack does occur, each Nato member will assist the country that has been attacked with any action 'it deems necessary'.
The RAF regularly flies sorties over the Black Sea's international waters, as well the Baltics and eastern Poland, to gather intelligence.
The role of the Rivet Joint aircraft is to hoover up electronic transmissions and communications - the plane is also known as a 'nuke-sniffer' for its ability to detect radioactivity.
British and US aircraft continued to conduct these reconnaissance flights after the hair-raising incident in September, but RAF surveillance aircraft are now escorted by Typhoon fighters while the US resorts to the use of unmanned surveillance drones.
Pentagon spokesman Brig. Gen. Patrick Ryder said last month that it is important to keep the Black Sea and the skies over it open to all nations.
'The Black Sea is a critical international seaway supporting many of our Nato allies, including Romania, Bulgaria and Turkey, and does not belong to any one country,' he said.
Ryder's comments came after yet another aerial incident in which Russian jets dumped fuel on and ultimately crashed into a US surveillance drone last month.