French Census: Au 1er janvier 2007 (...) la population de la France est estimée à 63,392 millions de personnes dont 61,538 millions en France métropolitaine.

So less than 1m difference, and possibly less if you take into account all the UK expats throughout the commonwealth, who are often in and out of the country.

For practical purposes, the populations are similar enough for overall economy comparisons to make sense. In any case, it is the relative trends that matter (and these cannot yet be ascribed to the effects of one country being run by a "dynamic" president and the other by a "crypto-socialist" PM...)

In the long run, we're all dead. John Maynard Keynes

Officially, the population of Britain is about 65 million, with estimates of increase suggesting that it might rise to 70 or maybe 75 million by 2030, or 2050 or some other fantasy time in the future we don't have to plan for.

However, even that may not be the end of the story, the Independent claims that the present real population may be much higher.

It is the statistic that dare not speak its name, though eventually it must. ......So don't forget you read it here first: the population of the UK is presently somewhere between 77 and 80 million.

Consumption - that's the thing. Based on what we eat, one big supermarket chain reckons there are 80 million people living in the UK. The demand for food is a reliable indicator; as Sir Richard Branson says, you can have all the money in the world but you can only eat onelunch and one dinner. I have a second, respectable, source. A major, non-commercial agricultural institution reckons there are 77 million of us in the UK. Again, its reckoning is based on what we eat.

However, whether the population is 65 million or 80 million, the reason why most commentators complain is that at least a third of that population, and probably the majority of that phantom population, are crammed into the south east. As that is where the commentators are also based, their impression is of a country desperately over-crowded.