Telepests: we have all had ‘work experience’ with them. A regular correspondent, Rohitkumar Gudka (Toy Box, London), sent me an email with the query: “Is there a scam about firms ringing up offering 20% off (utilities) bills on this contact number 00123456789?”

Although that number is rather stupidly obvious, a bit like using 1234 for your pin number or calling yourself AAAgrocer to get first listing in a directory, it does fool some people. But if you dial it you get a BT message that the number has not been recognised.

If you look it up online to try to discover its origins you get loads of entries. On one website there were 24 pages of complaints dating back from yesterday to five years ago.

The number apparently has been used by any number of call centres offering cheap electricity deals, timeshare offers, and other peculiarities such as a one-off £19 deal on the telephone preference registration (TPS) service. That’s my ironic favourite. TPS offers a free service to block such nuisance calls. Not that it can succeed in all cases, because it cannot do much about callers located abroad who ring you.

And by the way, if you are looking for a deal on utilities, try a broker’s outfit like MakeItCheaper.com because they don’t charge for their services and deal with all the big gas and electricity companies. They make on the commission and are completely impartial.