It couldn’t have been worse timing. Vince Cable calls for a more flexible immigration policy, and then a report comes out predicting the UK’s population will rise from 62 million today to 77 million by 2050. And yet it was good timing, too, because yesterday saw the announcement that the default retirement age will be scrapped from October next year. Yes, immigration is in the news again, but maybe it is time we started accepting some harsh reality.

Give credit where it is due, Vince Cable has been brave. He couldn’t have chosen a stronger tide of public opinion to swim against. If the Lib Dems had adopted a tougher policy on immigration during the election campaign, they would have won more seats. And since we live in a democracy, and since the UK public clearly want less immigration, then less immigration is what we should get.

But from an economic point of view, Dr Cable may well be right. The sword of Damocles, also called impending retirement of the baby boomers, hovers ominously. An interesting report in Foreign Affairs Magazine from a few months ago, said the ultimate solution to the demographic time bomb, in which the ratio of retired to working population across much of the developed world soars, lies in immigration. Or, for that matter we may also need emigration of retiring baby boomers to poorer countries where their care can be provided by a more youthful population, and provide a boost to the economy they emigrate to.

The difficulty lies in the rationale for immigration. It is clear that immigrants are often more dynamic than people who choose to work in their country of birth. Maybe this is the single biggest reason why the US has done so well; its economy is, after all, based on immigration.

The big problem with immigration into the UK lies in the benefit system. Immigrants who come to the UK with no intention of finding work, but merely to claim benefit, should be discouraged. Differentiating between immigration that adds to the economy and immigration that subtracts from it is incredibly hard.

There is a danger that in our zeal to curb immigration, some people with legitimate claims to come to the UK, or others who could bring real economic benefit, will get caught in the trap.

The gold medal won by Mo Farah in the European Championship is a high profile example of how immigration policy can be good for Britain. And yet if you read his story, it is the tale of a young man who came here when he was eight, but whose career in athletics was held back over doubts on whether he could re-enter the UK after representing us in tournaments abroad.

Of course, if we are unwilling to accept more immigration we will have to face up to the alternative, which is to work until we are much older. Now the government has revealed plans to ditch the compulsory retirement age.

It is contentious legislation. On one hand are those who say it is not fair, and that those who want to retire at 65 will be put under pressure to work longer. Others say it is hard enough to fire people in this country as it is, and now you can’t even get rid of them when they are old. Maybe next they will be banning the practice of terminating someone’s employment even after they have died. You can imagine the tribunal. “We accept that Mr Smith is now dead, Sir, but the fact is, you can’t terminate someone’s employment without giving them three written warnings first.”

In reality, there simply is only one alternative to extending the retirement age, and that is having a more accommodating immigration policy.

And yet, 77 million? That’s a lot of people. Maybe we should take a close look at what the population forecasts are saying. See: UK set for population explosion. See also: The demographic time bomb.