Image caption Study is the most common reason for immigration into the UK

Net migration rose by 21% last year, with 239,000 more people arriving in the UK than those leaving, the Office for National Statistics has revealed.

In 2009, the total for net migration had stood at 198,000.

The government has pledged to reduce net migration to the "tens of thousands" by 2015.

As part of that drive, the number of skilled workers from outside the European Economic Area who are allowed into the UK each year is being capped.

ONS estimates put long-term immigration in 2010 at 575,000, up slightly from 567,000 the year before.

But the long-term emigration figure saw a sizeable drop from 371,000 two years ago to 336,000 - the lowest level for six years.

"It's emigration that is, in a sense, the problem for the government at the moment," said BBC home affairs correspondent Danny Shaw.

"Work is the main reason why people leave the UK, and the numbers of people leaving the UK for work reasons is down considerably.

"So what it would seem is that the economy in the rest of the world [and the] lack of opportunities for jobs elsewhere is actually making people not want to leave Britain."

The detail of the ONS figures showed the number of people arriving in the UK for a definite job at a six-year low of 110,000.

Analysis Today's figures point to two really important elements of the equation which the government cannot control: Emigration and European workers. Immigration has stayed broadly the same but the figures show that fewer people are emigrating. For years, net migration has hardly been affected by the movements of European Union citizens largely because the number of EU workers arriving has been offset by the numbers leaving, including British citizens. But now, while fewer British citizens are going abroad, more EU workers have been arriving than leaving, particularly from Eastern and Central Europe. So why is the plentiful of supply of cheap Eastern European labour creating a headache for ministers? It is simply because their continued arrival, combined with the current falls in the numbers of all people emigrating, mean they will have to look elsewhere to hit their net migration target. Read Dominic's full analysis Follow Dominic on Twitter

Meanwhile, the total leaving the UK for work was at its lowest for three years at 179,000.

Study was the most common reason for entering the UK. Of a total of 228,000 immigrant students last year, three-quarters came from outside the EU.

Net migration into the UK from the so-called A8 countries - the Czech Republic, Poland, Hungary, Slovakia, Slovenia, Estonia, Latvia and Lithuania - jumped to 39,000 from 5,000 in 2009.

The range of figures released by the Office for National Statistics cover the calendar year of 2010, which saw a change of government in May - after an election campaign in which immigration was one of the main areas of debate.

"To be fair to the coalition government, they've only been in power for six months of these figures," our correspondent said.

"So I guess that the figures next year will be more instructive as to the direction of travel and whether they are going to meet their objectives."

Immigration Minister Damian Green said the period covered by the figures predated the government's "radical changes" to the immigration system.

"After almost two years of increasing net migration the figures stabilised in the last quarter," he said.

"This explains why the government radically changed immigration policy, from our first months in office, to drive the numbers down with a limit on economic migration and changes to student visas to ensure we attract the brightest and best whilst tackling widespread abuse of the system."

Shadow Home Office minister Shabana Mahmood said the figures undermine the coalition promise to slash net migration.

"These figures reveal the gulf between the government's rhetoric on immigration, and the reality we see in the official figures," he said.

Government promise

Media playback is unsupported on your device Media caption Sir Andrew Green: ''It's the equivalent of building the city of Birmingham every two years for the extra population, of which at least two thirds will be due to immigration'

Sir Andrew Green, chairman of Migrationwatch UK which campaigns for tougher controls, said the figures "lay bare the legacy" of the previous Labour government.

"The coalition government will have to face down some vested interests if they are to get anywhere near their target of tens of thousands," he added.

Matt Cavanagh, of the Institute for Public Policy Research think tank, said the figures highlighted stability in the numbers entering the country, alongside a continuing fall in those leaving.

"Politicians shouldn't promise what they can't deliver, particularly on immigration," Mr Cavanagh said.

"Before the election, Conservatives and Liberal Democrats said immigration was out of control; afterwards, they said they would cut it dramatically. Neither was true."