I have been receiving several telephone calls a day from a London number that does not leave a message.

The advantage of being able to store the numbers of your friends and regular contacts in the memory of your phone is that you are not always taking a chance when you answer it.

The risks of course are many and varying in irritation potential. If you are not good at bringing to a halt long conversations, for fear of offending the other party, then not answering when you are busy is a handy option.

And no one relishes the thought of dealing with those poor unfortunates with scripts who are chained to banks of computers calling randomly about ‘that accident you had last week’, your satellite TV or phone insurance or ‘can we tarmac your staircase while we’re in the area.’

Being ex-directory doesn’t help as often they are just cold-calling random numbers in the hope that someone will answer and then instantly wish upon them a plague of boils and Donald Trump’s hairdresser.

If I don’t recognise the number I wait to see if they leave a message. If they don’t do that then by my book they are up to no good and worthy of a swerve.

This particular number has phoned so often that I have checked it out on the internet.

It is a large and perfectly benign charity that I donated some money to after seeing a particularly moving appeal on TV. It was the work of seconds to make a small donation via my phone. This clearly entered my phone number onto their follow- it-up list.

Most of us at some point make donations to charities that touch us. We usually like to do it of our own volition rather than when irritated by being disturbed in our homes or approached by well-meaning young people with clipboards in the street.

The telephone has always been a partly unwelcome and intrusive domestic presence. ‘If I had wanted to talk to them I would have rung them’ – which I wouldn’t do because I wouldn’t want to annoy them.

The best aid to communication ever has been the letter, followed by the email and text. You send them when you want to; the recipient replies when they want to – if it all. Considerably lower down the take-a-risk list.

I have blocked the persistent caller.