London: When the British people voted to "take back control" on June 23, little did they know they were signing up for an "eye-watering" £58.7 billion ($98.76 billion) bill, partly due to the Conservative government's promise to slash migrant numbers to the "tens of thousands".
The staggering figure was revealed in the British government's seasonal budget update, known as the Autumn Statement.
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Chancellor of the Exchequer Philip Hammond announced a delay in the planned budget surplus and a doubling in government borrowings to £233 billion over the next six years. Public sector net debt will now peak at 90.2 per cent of GDP and remain higher than the forecasts in March, before the referendum on European Union membership.
Economic Secretary to the Treasury Simon Kirby conceded the number was an "eye-wateringly large figure". Forecasts for economic growth have slashed from 2.2 per cent to 1.4 per cent in 2017.
Higher inflation caused by the weakening British pound, which crashed after the referendum, will push up the cost of living and stall growth in real wages.
Mr Hammond said the British economy had confounded the world with its resilience since the vote. "An economy which the IMF predicts will be the fastest-growing major advanced economy in the world this year," he told the House of Commons.
"An economy with employment at a record high – and unemployment at an 11-year low."
![Politicians Boris Johnson, Gisela Stuart and Douglas Carswell with a mock cheque referring to the costs of EU ...](/web/20161125124110im_/http://www.smh.com.au/content/dam/images/g/p/2/o/p/r/image.related.articleLeadwide.620x349.gsw726.png/1479968391969.jpg)
But the Labour MP Pat McFadden, a leading supporter of the Open Britain campaign, said the true cost of Brexit had been exposed.
The Brexit bill is in: £58.7bn https://t.co/fAotRTD9hd pic.twitter.com/htZHvIlgJM
— Open Britain (@Open_Britain) November 23, 2016
![Brexit promised Britons they could take back control. It comes at a hefty price.](/web/20161125124110im_/http://www.smh.com.au/content/dam/images/g/p/d/3/f/f/image.related.articleLeadwide.620x349.gsw726.png/1479968391969.jpg)
"Today, the real picture of Britain's post-Brexit economy emerged – borrowing up, growth down, investment lower, prices higher," he said.
"The eye-watering £58.7 billion Brexit borrowing bill means less money for public services, not more as we were promised."
![British Chancellor of the Exchequer Philip Hammond.](/web/20161125124110im_/http://www.smh.com.au/content/dam/images/g/r/u/a/m/l/image.related.articleLeadwide.620x349.gsw726.png/1479968391969.jpg)
The independent Office for Budget Responsibility (OBR) calculates the costs of Brexit by taking into account the costs of lower migration, lower productivity growth, higher inflation and ongoing low interest rates.
In October, British Home Secretary Amber Rudd vowed to stop migrants "taking jobs British people could do" and announced harsh new measures aimed at foreign workers and students, including Australians. An estimated 87,000 Australians live and work in the United Kingdom.
Prime Minister Theresa May has pledged to reduce net migration, which hit a record high of 327,000 in 2015, to the "tens of thousands".
But Liberal Democrat MP Norman Lamb said the Autumn Statement showed why Britain must remain "open to talent from around the world".
"The OBR has set out in black and white the facts that [Foreign Secretary Boris Johnson] and other Vote Leave leaders can't bring themselves to hear – immigration is good for our economy, and hard Brexit will make our country worse off," he said.
In a briefing with foreign journalists Mr Kirby, who backed Remain, told foreign journalists that cutting migration would bring with it costs.
"There are positives and negative effects to migration economically," he said.
"Migration does have an impact on GDP, it does have an impact on productivity and we've been clear that the British people voted on June 23 to leave the EU because they wanted to control migration," Mr Kirby added.
"And the Prime Minister's been very clear that it's our intention to reduce the numbers to tens of thousands rather than the hundreds of thousands that they currently are."
But he said the international business community should not be put off by the gloomy budget figures.
"I am optimistic that the UK remains open for business and we have a sensible and secure way forward in fiscal terms."
Mrs May has said she will trigger Article 50, the formal and technical process for leaving the EU, in March 2017, and the OBR predicts Britain will end up leaving two years later, in April 2019.
However the OBR doubted the government would meet the target for migrant numbers, meaning the Tories could find themselves bearing the economic cost of lowering migration as well as the political pain for not slashing numbers by enough.