Net migration to Britain reached a record high last year, official data showed on Thursday.

It reached 252,000 in 2010, the highest figure since records began, according to the data from the Office for National Statistics (ONS).

The government has said it wants to slash net long-term immigration to less than 100,000 a year by the next election in 2015.

The ONS data showed the total number of people entering the UK remained steady at 591,000, while the number leaving was at its lowest since 2001 at 339,000.

The main reason for immigration continued to be to study -- numbers rose from 211,000 in 2009 to 238,000 last year.

Fewer people emigrated from the UK for work-related reasons in the year ending March 2011, down to its lowest in five years at 174,000 compared to 203,000 the previous year.

Immigration Minister Damian Green defended the figures, saying the government was still on track to reach its target.

Latest quarterly figures show a decrease in the number of student and work visas issued compared to a year earlier -- an early sign that our policies are starting to take effect, he said in a statement.

The latest net migration figures are also encouraging, showing a fall since the recent peak in September 2010, but we are clear there is much more to be done.

Data from the ONS released on Wednesday projected the total UK population to reach 73.2 million by 2035 and up to 81.5 million by 2060, up from 62.3 million now.

Based on upper estimates for fertility, life expectancy and migration, Britain's population could reach 77.7 million and 94.8 million in the same time frame, it said.

At over a quarter of a million in 2010, net migration was the highest it has ever been, said Andrew Green, Chairman of Migration Watch UK, an independent think tank that lobbies to keep the UK population close to its current level.

It was more than five times the level of 1997 when Labour came to power. It is absolutely vital to get this down to less than 40,000 if we are to keep our population below 70 million, he added.

Labour's shadow Immigration Minister Chris Bryant said the government should come clean about the figures.

These figures just go to show you can't trust what this government and this Home Secretary say about immigration, he said in a statement.