By Mark Easton
Home editor, BBC News
Two apparently contradictory stories are emerging from the immigration debate.
The first is a political and social argument: that Britain needs to do more to limit the numbers of migrants who are coming here because of pressures on public services and community cohesion.
The second is an economic argument: that key industries - construction, hospitality and agriculture - need the government to encourage more migrant workers to come because of labour shortages.
The report from the Institute for Public Policy Research (IPPR), a left-leaning think tank which has been broadly positive about immigration, attempts to provide a statistical basis on which to hang the arguments.
It has looked at the impact of East European migration since the so-called A8 countries joined the EU in 2004.
The analysis is based on existing UK data and surveys and focus groups conducted in Poland.
The IPPR's conclusions may provide solace to those who fear immigration is too high but will be greeted with alarm by some businesses who currently rely on migrant labour.
The headline figure of one million arrivals from Eastern Europe is much higher than the government's original estimate.
Whitehall officials thought only about 60,000 would have come by now.
But the IPPR also estimates that half a million of those have already moved elsewhere and many more will go soon.
Immigration figures are notoriously difficult to assess because the UK does not count everyone in and everyone out.
However, the analysis has been discussed by official and independent statisticians who have not challenged the methodology.
The signs are, says the IPPR report, that arrivals from countries like Poland have begun to "slow substantially" and there are good reasons for thinking there will be an increase in the numbers returning.
As the British economy slows down, countries like Poland are seeing rapid growth.
Other European countries which have restricted migrant workers are now opening their doors. And the weak pound against currencies like the Polish zloty means pay rates here are much less attractive.
A recent survey by the communities and local government department has identified places where social cohesion appears fragile.
Six of the 10 areas with the worst community relations have seen large numbers of East European migrants, including Boston, in Lincolnshire, Fenland and nearby South Holland.
Immigration and race relations are at the top of voters' concerns and such tensions have prompted ministers to try to restrict numbers coming to live and work in the UK.
But go to Perthshire and it is a very different story. Here too they worry about immigration. Not that there are too many migrants, but that there are not enough.
Pitlochry, for instance, is a town whose economy has become reliant on East European workers.
At the local Scotland's Hotel, the haggis is cooked by a Polish chef and served by a Hungarian. The bedrooms are cleaned by young Czechs.
But with almost full employment locally, managers fear they will be left high and dry if supplies of migrant workers dry up.
Donald Allan, from the Crerar Hotels group, is worried. "We are trying our utmost to keep our people," he says.
"If they go home, currently I don't know where we will replace our European colleagues."
The tourism industry has expanded thanks to overseas labour and there are fears it could contract as quickly.
Fruit and vegetable farmers in the area are also worried about labour shortages, with some blaming government immigration policies for threatening their livelihoods.
At West Haugh Farm, near Blairgowrie, Peter Thompson fears his crops of soft fruit, promised to the supermarkets, could rot in the fields because the Home Office has cut the number of seasonal workers allowed to come to the UK.
"If we can't pick it that's what will happen" he says.
"Last September-October we just struggled through but given that we have a lot fewer applicants this year we envisage a lot more problems."
What the IPPR report reflects is the complexity of the immigration debate. The figures can only be best guesses, but the trends seem clear enough.
Britain is likely to see a significant fall in the numbers of Eastern Europeans coming here.
Some will argue that is a good thing.
But for businesses in Scotland and beyond, the consequences could be very serious.