*Ahem*, post #10. I did the research, all you had to do was read it! Even in the 1960s we'd been slipping towards the American usage and it was getting confusing. In 1974 Wilson confirmed that, as far as government statistics were concerned, we would be using the America measurement from now on.Took a while to filter through all of society, but as the posts of the younger generation have confirmed - filter through it did.When I were a lad still at school - i.e. through the sixties - a billion was indeed a million million. Don't know when it changed, or whether it just happened over time that we moved in to the Americanism.....