Incident last October saw Russian navy and air force confront British destroyer, security official claims.
Britain’s government is investigating how secret defence documents, outlining the movements of a warship that led to Russia firing warning shots off the Crimean coast, were found at a bus stop in England.
The Ministry of Defence (MoD) said on Sunday that an employee reported lost documents last week and that an investigation had been launched.
“It shouldn’t be able to happen,” Brandon Lewis, minister for Northern Ireland, told Sky News. “It was properly reported at the time … there’s an internal investigation into that situation.”
A member of the public, who wanted to remain anonymous, contacted the BBC after finding 50 pages of classified information in a soggy heap behind a bus stop in Kent early on Tuesday.
The papers included one set of documents that discussed the potential Russian reaction to HMS Defender’s travel through Ukrainian waters off the Crimea coast on Wednesday, according to the BBC, while another laid out plans for a possible British military presence in Afghanistan.
The MoD said that HMS Defender “conducted innocent passage through Ukrainian territorial waters in accordance with international law” and that “all potential factors” are considered when making “operational decisions”.
The HMS Defender is part of the UK Carrier Strike Group currently heading to the Indo-Pacific region.
However, it was announced earlier this month that it would be temporarily breaking away from the group to carry out its “own set of missions” in the Black Sea.
The Type 45 destroyer caused a clash with Russian forces on Wednesday when it travelled through waters south of the Crimean Peninsula, which Russia unofficially annexed from Ukraine in 2014.
Moscow responded by having several aircraft shadowing the ship at varying heights, the lowest being approximately 500 feet (152 metres).