'If these revised figures are accurate, they make clear that net migration remains far too high'

Friday 23 August - Britain’s Office for National Statistics (ONS) has admitted its own figures underestimated long-term migration between 2009 and 2016 by almost a quarter of a million.

The statistical agency discovered the error after examining Department for Work and Pensions (DWP) data and comparing it to their own estimates based on the International Passenger Survey (IPS), according to The Times.

Britons are often surprised to learn that the country’s migration statistics are not measured by counting people in and out of the country and monitoring their length of stay etc., but through a clipboard-based survey originally devised in the 1960s to guesstimate tourism and business travel trends.

A relatively small number of people — measured in thousands, while the number of people entering and leaving the United Kingdom is in the hundreds of millions — are approached at a relatively small number of entry points to Britain, at certain times of day, and asked for information about where they come from, why they are coming, and how long they intend to stay, with the ONS extrapolating its immigration statistics from the answers they receive.

Travellers are under no obligation to speak to the surveyors, and the honesty of their answers has to be taken on faith — so that 'it is possible for migrants to enter on short-term visas and — unless they notify the authorities of their intention to stay longer or are really, really unlucky and are picked up in a Border Force raid — stay in the UK or leave the country years later without showing up in the official records', according to the BBC.

The ONS believes its estimates will become more accurate as comparing IPS estimates to data held by government departments becomes more standard — and indeed its figures could be revised yet again once more information has been analysed.

'The number of EU nationals here is apparently much greater than we had been given to believe. Meanwhile, the high numbers from outside the EU continue apace, he added.

'Brexit is a golden opportunity to restore a degree of control yet much more will need to be done beyond that. Indeed, 30 million people wish to see reductions in immigration.'

'Whether the question is how to meet the net migration target or what to do about international students, the truth is that the data were simply not robust enough to be picked apart in such detail,' she added — although the Tory Party’s long-standing but never realised pledge to reduce net immigration “from the hundreds of thousands to the tens of thousands” has now been dropped by Boris Johnson, in any case.

Breitbart London has reported many times on the seemingly inadequate nature of ONS migration statistics, with the massive discrepancy between IPS-based estimates of the number of new migrants and the number of National Insurance numbers being issued to foreigners being a particularly glaring indication of their likely inaccuracy.