This is indeed a bad security breach by a senior official.

What on earth was he doing taking Top Secret STRAP material of this sort out of the building?

One of my first Blogoir posts described a grisly experience I had with FCO Security twenty years ago after a I passed a journalist a rather banal but Confidential document I had written.

This episode is far more serious. Really secret stuff left lying around.

In one way we should expect more breaches, simply because there are far more documents sloshing around now; the likelihood of some fathead losing one now and then is therefore all the higher.

The incompatibility and technical ring-fencing of the various top-level security computer systems round Whitehall (at least this was the case in my last time in London a few years ago) likewise mean that actual papers need to be carried from one building to another. And they can be mislaid.

Some top officials also have specialist laptops available for carrying Top Secret material, which melt into malodorous jelly if an unauthorised attempt is made to open and read them.  

It all boils down – as ever – to the human factor. Once upon a time the FCO Resident Clerk was sunning himself on the FCO roof when a Secret message came in to Churchill from Stalin on the FCO system, and was brought to him to action on to No 10.

Imagine his consternation when a gust of wind blew said message away over the parapet and into St James’s Park.

Life – somehow – went on.

Note: sign of the times that the plucky citizen finding these Top Secret papers on the train yesterday handed them to the BBC, not the police. Dipstick.