Help Please To ID Overprint On GB Qeii Stamp

I presume sort some of private overprint, but was it applied by someone playing around or ?? Seems odd to overprint the value.

There were many different commercial security overprints used in this period, having a similar purpose to perfins.

I believe SEGB is for South Eastern Gas Board

I am almost certain that's going to correct, although I'm no expert. But I do have an number of overprints on Wildings for gas and electricity boards, often with words rather than just initials. (I'll see if I can get a scan or two later.) As said, they serve the same purpose as perfins. Why gas and electricity boards had them instead of perfins, I'm not sure. They were nationalised at the time, as was the Post Office, so maybe it was an in-house trial to see if they were better or cheaper than perforating the stamps.

Thank you both for the informative replies. The overprint looks very amateurish to me so I just assumed someone was playing around Now I know better.

Your stamp is a commercially overprinted stamp and was used as a receipt.

They serve the same purpose as perfins, only difference being that you seldom, if ever, see a perfin used as a receipt, although, I am sure they were.

You might want to give this website a check? http://www.cosgb.org/

Chimo

Bujutsu

I've found a few...

South of Scotland Electricity Board:



East Midlands Gas Board:



Marshland Poo ?? Not sure what this is!



Edinburgh Corporation:



South of Scotland Electricity Board on a Machin:

Hi Ringo,

Your "MARSHLAND POO" overprint is actually "MARSHLAND RDC" for Marshland Rural District Council in West Norfolk.

Stamps with these commercial overprints were used to collect the 2d (and earlier the 1d) duty on receipts (as could be done using ordinary 2d stamps).

While there was a similarity with perfins in that overprinting helped control pilfering of the stamps (and both methods stopped the stamps being redeemed for cash at a post office), there were differences.

Adding a perfin did not in itself cancel a stamp from a postage perspective but a commercial overprint did so a stamp with a commercial overprint couldn't be used to pay postage.

Indeed you can see here the "paid" stamp on the postage stamp.

As nigelc has mentioned, these overprinted stamps could not be used for postage (although some were... especially when Stamp Duty was about to be abolished in the early 1970's). They are therefore revenue stamps if they have commercial overprints.
Perfins are valid for both postal and revenue use.