David Cameron's aim of cutting net migration to below 100,000 has been dealt a devastating blow as official data confirmed the number has jumped again, reaching a record high.
The Government's chances of achieving such a fall in the key measure appeared more remote than ever as figures showed it now stands more than three times higher than the goal.
Estimated net migration to Britain - the difference between the number of people entering and leaving the country - was 330,000 in the year to March.
This is 10,000 higher than the previous peak recorded in the year ending June 2005 when enlargement of the EU saw a surge in arrivals from eastern Europe. It was also an increase of more than a third compared to the same period last year.
Immigration Minister James Brokenshire admitted the findings are "deeply disappointing", while critics described them as a "shocking" indication that the 100,000 target would not be met.
It is the fifth consecutive quarterly rise in the index and was driven by a record 269,000 EU citizens arriving in Britain - an increase of a quarter compared to the previous year.
A jump of more than a quarter in a year took the total number of people coming to Britain for work purposes to 290,000, with the latest employment figures showing the number of EU nationals in jobs has increased by a quarter of a million in a year.
One in eight people born abroad
Separate data published at the same time also confirmed Britain's foreign-born population has surpassed eight million for the first time, meaning one in eight people living is born abroad.
The Office for National Statistics figures also showed:
:: Overall Immigration - the number of people coming into the country - was 636,000, the highest total since current records started a decade ago.
:: The number of EU migrants arriving jumped by a "statistically significant" 56,000. A total of 284,000 people arrived from outside the bloc after a more modest increase of 23,000.
:: The number Romanians and Bulgarians arriving in the UK has almost doubled to 53,000. Restrictions on people from the two countries working in the UK were lifted in January last year.
:: Polish is the most common non-British nationality, with an estimated 853,000 people from the country now living in Britain.
:: Asylum applications in the 12 months to June totalled 25,771 - the highest figure for any 12-month period since the year to September 2009.
Labour MP Keith Vaz, chairman of the parliamentary home affairs committee, said the net migration figures are "shocking".
"Only one month ago Theresa May told the home affairs committee that net migration of under 100,000 was her target," he said.
"This is clearly not going to happen. Broken promises on migration do not build confidence with the public. We need a radically different approach."
Lord Deddington, chairman of campaign group Migration Watch UK said the figures underline the need for "serious concessions" in forthcoming negotiations over Britain's relationship with the EU.
He added: "Net migration at one third of a million a year is clearly unsustainable."
Madeleine Sumption, director of the Migration Observatory at the University of Oxford, said migration levels are now comparable to levels seen in the middle of the last decade when eastern European countries including Poland and the Czech Republic joined the EU.
"What this means for the UK is subjective," she said "There is no objective way to decide what the 'right' number of migrants is, and reasonable people will disagree.
"What is clear is that reducing net migration to below 100,000 remains a distant prospect, at least under current economic conditions and policies."
In 2011 Mr Cameron pledged to reduce the net migration to five figures "no ifs, no buts" in 2011.
The target was missed in the last parliament and was referred to as an "ambition" in the Tories' election manifesto. Following the poll, Mr Cameron insisted the aim was still achievable.
The Government insisted it is taking action to control immigration and claimed the figures should act as a "wake up call" for the EU amid an unprecedented surge of people arriving on the continent.
"These stark figures are deeply disappointing," said Mr Brokenshire. "While these figures underline the challenges we need to meet to reduce net migration, they should also act as a further wake-up call for the EU.
"Current flows of people across Europe are on a scale we haven't seen since the end of the Second World War.
"This is not sustainable and risks the future economic development of other EU member states. It reinforces the need for further reform at an EU level as well as within the UK."
He said the new Immigration Bill will address illegal working, "pull factors" that draw migrants to Britain and the availability of public services "which help them to remain here unlawfully".
Mr Brokenshire said the Government has slashed student fraud, struck off nearly 900 bogus colleges and toughened access to welfare and housing but admitted there is "much more to do".