Precancels Canada and commercial overprints Great Britain

In my collection I also have stamps with precancels and commercial overprints from Canada and Great Britain. Below you can see some pictures of the stamps.

Precancels Canada

commercial overprints Great Britain

These stamps are (not) real precancels. They are for revenue purposes only not valid for postage. At the time all receipts, checks etc attracted a duty of 2d. Some had these pre-printed on the documents but others were validated by the use of 2d postage "&" REVENUE stamps. The ones here are mainly from utilities (Gas Electricity,water supply etc) and have obviously been removed from the documents concerned. They are not particularly valuable but are quite interesting. On the original documents ( other than ordinary receipts) they can have social history interest.