A fine Alvis 12/70... but... What? When? And who? (upd. Mells Somerset!)

Lock-ups were established before we had formal county police forces and proper village police stations - sometimes they were used to hold suspected miscreants until the local circuit judge arrived in the nearest town for a trial, but most often just to hold drunks overnight until they'd sobered up, when they would be hauled in front of the magistrate. The buildings were windowless and usually didn't have a chimney either: once the door was locked and barred there was no way out!

https://en.wikipedia.org/wiki/Village_lock-up

Possibly the only one still in use is on Sark in the Channel Islands - although these days it is officially a jail, even though it only has a capacity of two!

http://sightbywalk.blogspot.co.uk/2011/03/worlds-smallest-prison-sark.html

So for those of us who are not on the isle of Great Britain, what was the building used for, and what is on the inscription on the plaque by the door.

"Lock up" could refer to a jail, but perhaps it is a storage shed, or maybe something else (garden entrance)?

Well done Richard! Looking at Google Streetview, it seems a positive identification of the location. The car appears new or nearly new so I'll have a look in the Works records for delivery of a black SC 12/70 to the Bristol/North Somerset area in the colder months to see if I can speculate as to which car.

I agree this is the old lock up in Mells, I visited the village in the summer and there is no doubt I cannot help with the ALVIS though, it was not there!

The building, being windowless and with a stout door, is typical of the village lock-ups which were found all over the country. Lots of them survive, but a lucky hit on a search on Geograph led me to this one. It's in Mells in Somerset and - if not the actual one in the picture - seems to be of an identical design.

http://www.geograph.org.uk/photo/2758926

Since that picture was taken, the ivy has been removed and the trees behind felled or thinned. It's at the junction of Gay Street and Rashwood Lane. Looking at it on Google Street View, I'd be 90% certain it's the same building.

editor: bravo Richard! You don't need to be a detective not only to recognise the similarity. The the large stones/bricks plus surrounding ones low left of the door makes us raise your certainty to a mere 99,5 %...

Is this a "Folly" of some kind ?
http://www.follies.org.uk/follymaps.htm
or Beacon, Tollbooth, Chapel.
England is full of them !
Stuart