These envelopes are not issued by postal authorities, but by those wishing to commemorate the Centenary of the Boys' Brigade in 1983. Usually there is a special postmark.
Commemorative Cover issued by Benham (UK)
It is signed by the stamps' designer, Brian Sanders.
There is an accompanying card which gives a brief history of the Boys' Brigade and lists some of the commemorative events happening in the Centenary year.
Commemorative cover issued by Stuart (UK)
Apologies for the postmark!!
There is an accompanying card gives a very brief history of each organisation.
Centenary Camp, New Zealand, with Solomon Island Stamps
There was also a commemorative postmark
This is a mixture of the Jersey, Guernsey & UK stamps plus postmarks that were used when these stamps were issued by the relevant postal authorities. According to some information I have when I received these covers, there are only 10 such envelopes in the world (wow!)
Scottish Philatelic Congress honours Sir William A. Smith
Scotland, UK
9th April 1983
Benham "silk" envelope, bearing a postmark commemorating the Centenary International Camp, Scone Palace, Perth, Scotland, UK
There is an accompanying card which gives a brief history of the Boys' Brigade and lists some of the commemorative events happening in the Centenary year.
20th August 1983
Centenary International Camp, Scone Palace
Perth, Scotland, UK
20th-30th August 1983
Alba Stamp Group honours Sir William A. Smith
Scotland, UK
An accompanying card gives a brief history of the Boys' Brigade and describes some of the work of the Alba Stamp Group.
4th October 1983
Glasgow, Scotland, UK
Cardiff, Wales, UK
Signed by the late Viscount Tonypandy (George Thomas) lifelong Methodist, and speaker of the House of Commons from 1976-1983.
The card insert gives a brief history of the Boys' Brigade. The reverse gives some information of the BB in Wales, explains the cover design, and links it in with Cestyll '83, the festival of castles in Wales.
Brighton, Hove & District Battalion, England, UK
Luton, England, UK
Signed by the late Eric Morecambe
An accompanying card gives a brief history of the Boys' Brigade and the formation of the Luton & District Battalion.
Preston, England, UK
An accompanying card gives a brief history of the Boys' Brigade in the North-West of England, and describes the design of the handstamp.
Australia
This is a pre-printed envelope. It bears the postmark commemorating the Australian centenary camp.
The rear of the envelope gives a brief outline of the work of the Boys' Brigade.
BB on Stamps