On 7 Aug, 15:20, "Man at B&Q" wrote:

As a caller, you would also be charged if they had an answering
machine that took the call.


Not so. The specific situation given was that of calling someone who
was on the phone. Even if they had an answer machine in this
situation you would still get an engaged tone and would not be charged
for the call. You can then try again later.

Andrew