Knock on your average door in these Great British Isles and ask someone what bugs them about the country. The chances are before not too long has passed they'll mention immigration.
Politicians, whose job it is to find out what their constituents think by doing exactly this, know all too well that this evergreen problem of British politics remains as potent as ever. Immigration is vital for the prosperity of the British economy, but its positive effects on GDP are not felt as directly as the pressure new arrivals can put on local services.
So when the government launched its e-petitions system last year it didn't take long before the public were invited to express their concerns. There are now over 143,000 signatures to the 'no to 70 million' e-petition, which opposes the UK's population growth to that number in the next 20 years or so. This increase is the equivalent of seven cities the size of Birmingham, it warns. It will have a huge impact both on our quality of life and on our public services, yet the public has never been consulted".
Today MPs will debate the e-petition. Its champions are two backbenchers, Labour's Frank Field and the Conservatives' Nicholas Soames, who write in today's Sun that it is "crunch time" and that if "mass immigration is allowed to continue it will cause havoc in our society". With the government borrowing £1 for every £4 it spends, the pair don't see how we can possibly pay for all these new people.
In opposition the Conservatives appreciated these concerns. I watched Labour candidates fail to win over sceptical voters as they mounted an overly-complicated defence of their 'points-based system'. Tory candidates, by contrast, simply rolled out a soundbite pre-prepared by their party on high. Immigration, they promised, would be reduced from the hundreds of thousands to the tens of thousands.
Although Cameron and co had to enter into coalition, this pledge has survived. It remains the government's intention to achieve just 99,999 new arrivals by 2015 at the latest. Yet it is not going far enough.
Statistics out last week showed estimated long-term total immigration to the UK in the 12 months to December 2011 was 566,000, according to the Office for National Statistics. That is significantly down on the 591,000 in the year to December 2010 and is the first major fall since 2004. It is a move in the "right direction", ministers said. But it doesn't look like being nearly enough.
Everyone in Westminster knows what the problem is. There is a growing obsession with the statistics themselves, which many politicians now believe aren't quite right.
Today the business, innovation and skills (bis) committee followed the Commons' even more influential public accounts committee in calling for the way the figures are calculated to be revised. The problem, they say, is that the government shouldn't be counting overseas students in its net migration figures. About 15% of this group stay in the country when they shouldn't, making it an area of real vulnerability for the struggling UK Border Agency. Too big a problem not to count. On the other hand, overseas students form such a big chunk of the total that the easiest way to lower the immigration figures is to lower the number of overseas students.
Bis committee chair Adrian Bailey says the government's approach is already having a "detrimental" effect on the UK's ability to increase its share of the overseas student market. Our universities get much more cash from this very lucrative section of their clientele than they do for homegrown students, so are desperate not to lose out. Some go too far, like London Met, which the government clamped down on last week. The majority of universities argue they are being victimised for a policy concern which doesn't really have anything to do with them.
Flawed immigration figures mean only one thing: the issue is doomed to continue to irritate and frustrate. Changing the statistics will leave the public confused and angry, feeling betrayed and deeply suspicious that promises have been broken.
From concerns on the doorstep to the complex nitty-gritty of Whitehall, the immigration question has somehow become very unclear. Ministers are unlikely to succeed in their goal without moving the goalposts. So as the number of people living in the UK slowly creeps upwards, the simmering tensions of immigration will only continue to increase.