Help Identifying This Stamp ( British? 6d)

I cannot find this stamp anywhere, I'm not even sure about the country. I came accross this stamp in a sparsly populated 1949 album.

Might be a cut out? It is British, no doubt about that though.

What do you mean by cut out?

Postal stationery.

As already mentioned it is a postal stationery cut-out. I cannot remember what rate or service the 6d covered but it was a hefty sum in those days.
The designs for these "stamps" were meant for an emergency as all GB low value postage stamps were printed by Harrison. The Post Office was worried that they were the only supplier so had designs created for emergency letterpress stamps. Stamps were never issued but the design was used for postal stationery.

The sixpence was used on Air Letters:

http://www.ebay.ca/itm/George-VI-Ai...380927409591

I like the dated cancellation / postmark. LONDON S.W. (South West) / 11:15 A.M. / 8 SP (September) / 56 (1956).

Monarch shown is King George VI (6th) .