On 25 Jul 2019 09:37:03 +0100 (BST), Natalie Amery
wrote:

In article ,
Roland Perry wrote:
If I buy a first class stamp, I have a legal contract with the Post
Office (to deliver one letter). But when they talk about 'contracts'
they mean long term high volume business.

Actually, you don't have a legal contract with the _Royal Mail_ until
you post the stamp; all you have is an offer to treat.

And you bought the stamp from the Post Office with a contract of sale.

The stamp is an undated voucher involving receipt of a future service
so there is a continuing contract started when the stamp was purchased
and finishing when the eventual postal item is delivered. The Post
Office/post office is acting as an agent of Royal Mail when it sells
the stamp.