Chris White, of Idstone, Loddiswell, writes:

I was interested to read Jim Martins' letter on the subject of internet scammers as my wife and I have received similar calls.

Should we ever receive another such call, our son, who works in software engineering, advised as follows:  Keep them talking as long as possible, pretending you are doing as they ask and having some phoney passwords etc prepared in advance. This way you are costing them time and money. 

Then, when you have strung them along for as long as possible, blow a whistle loudly down the phone.

My wife was called last week for, I believe, the third time from the scammers and managed to do the pretence and long chat but, alas, the 'Acme Thunderer' whistle I once owned had long since disappeared.