Britain's defence ministry said on Monday that it was investigating how nearly 50 pages of secret military documents were lost by a senior ministry official and ended up at a provincial English bus stop.

The BBC reported that the classified documents - including some relating to Afghanistan and others analysing Russia's potential reaction to the passage of a British destroyer through the Black Sea - were found on Tuesday. 

-A number of Ministry of Defence classified documents were lost by a senior official early last week. The individual self reported- Jeremy Quin, minister of state at the defence ministry, told lawmakers. 

-The documents lost included a paper that was 'Secret - UK Eyes only".It appears this was a mistake made by an individual- Quin said. 

'UK Eyes Only' means that the document is only distributed in the United Kingdom and not shared with allies. It was unclear how and why such documents ended up at the bus stop or whether or not they were copies or originals.

The documents were found by a member of public who handed the papers to the BBC which published a news story. The BBC has handed the documents back to the ministry, Quin said.

Quin said Britain had informed the United States of the situation and that the investigation would look at the security procedures around the printing of the classified documents.