Top secret Ministry of Defence documents have been found in a ‘soggy heap’ at a bus stop in Kent.
Fifty pages of documents reveal details about HMS Defender and the British military.
They allegedly show officials had predicted Russia may respond ‘aggressively’ to the ship’s passage through Ukrainian waters off the Crimea coast.
Other pages reportedly cover potential plans for a UK military presence in Afghanistan after the US-led Nato operation ends.
A man turned them over to the BBC after realising the sensitive nature of the documents.
An investigation has been launched amid claims they ‘came from the office of a senior official at the MoD’.
The HMS Defender’s ‘innocent passage through Ukrainian territorial waters’ was discussed at a high level as late as Monday, according to the BBC report.
The documents are said to consider three potential responses – ranging from ‘safe and professional’ to ‘neither safe nor professional’.
One presentation warned ‘it is highly likely that RFN (Russian navy) and VKS (Russian air force) interactions will become more frequent and assertive’.
The Russian defence ministry said on Wednesday a Russian warship had fired warning shots and dropped four bombs in the north-western part of the Black Sea.
But the Ministry of Defence disputed this version of events, saying Russia was undertaking a pre-planned gunnery exercise in the Black Sea.
Northern Ireland Secretary Brandon Lewis told Sky News he is aware of the bus stop discovery.
He said: ‘It’s something none of us want to see and shouldn’t be able to happen.
‘It was properly reported at the time into the Ministry of Defence, there’s obviously an internal investigation into that situation as well, and I’ve got to allow… the MOD to work through that investigation to understand exactly how this managed to occur.’
An MoD spokesperson said an employee had reported the loss of sensitive defence papers, adding: ‘It would be inappropriate to comment further.’
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