According to the Office for National Statistics, for the first time there are more people aged over 65 in the UK than there are people aged under 15, and the fastest growing age cohort is the over-85s. The problem is that rising life expectancy is coinciding with low or falling fertility rates - and this is an economic time bomb. At present in the UK there are four people of working age supporting each pensioner but within, say, 30 years this will have fallen to 2.5 people.

Soon I will be 72 and, assuming I get to 85-plus, I am not only going to be a nuisance but, according to one report I have read, I shall be dangerous. Actually there are three Ds: doddery, dependent and dangerous.

The gloomy prediction is that us oldies, many with inadequate pensions, will not only be an economic burden but we will be competing with you younger folk for increasingly scarce resources – jobs, housing, exhaustible fossil fuels, food and water, the NHS and so on.

Solutions are easier said than done, but here are a few:

• old people should work until they drop (the participation rate for over-65s is currently only 7 per cent – and that includes me);

• we should boost labour output with more working women and/or more immigrants;

• we should invest heavily in lifelong learning so that an ageing population develops new skills and remains competitive.

The population time bomb may be every bit as serious as climate change. Doing nothing certainly doesn’t seem a sensible option. Or am I just being paranoid?