Net migration into Britain has risen slightly as fewer British and EU citizens emigrated from the country, fresh figures have revealed.

A net flow of 176,000 migrants came to the UK in the year to December 2012, up from 153,000 in the year to September 2012, the Office for National Statistics (ONS) said.

The increase was driven by a drop in the number of migrants leaving Britain, which fell from 351,000 to 321,000, while the number of immigrants arriving in the country also fell from 566,000 to 497,000.

Prime Minister David Cameron and Home Secretary Theresa May want to reduce net migration from non-EU countries to less than 100,000 before the next election in 2015.

There has been a "statistically significant" decrease in the net migration of citizens from outside the European Union (EU) to 157,000 in the year ending December 2012 from 204,000 the previous year, the ONS said.

This was driven by a drop in immigration of non-EU citizens, particularly in the number of citizens of New Commonwealth countries, which include African countries such as Botswana, Kenya and Malawi and Indian subcontinent countries such as Bangladesh, India and Pakistan. The drop in New Commonwealth citizens immigrating to the UK - from 151,000 in the year ending December 2011 to 97,000 in the year ending December 2012 - is as a result of fewer people arriving to study in the UK from those countries.

Immigration minister Mark Harper said: "Net migration is down by a third since its peak in 2010. Our reforms are working and are building an immigration system that works in the national interest. We have tightened immigration routes where abuse was rife, but are still encouraging the brightest and best to come here to study and work. Immigration from outside the EU is now at its lowest level for 14 years. At the same time, there has been an increase in the number of sponsored student visa applications for our world-class universities, and an increase in the number of visas issued to skilled workers. We are committed to bringing net migration down from the hundreds of thousands to the tens of thousands. We are working across government to protect public services and ensure our welfare system is not open to abuse. The Immigration Bill, which will be introduced later this year, will make it easier to remove people who have no right to be in this country."

A total of 58,000 immigrants arrived from countries which joined the EU in 2004, including Poland, the Czech Republic and Lithuania, down from 77,000 the previous year.

The number of immigrants arriving for study in the UK is now similar to the estimated number of people arriving in the UK for work, the ONS said. Around 180,000 immigrants arrived in the UK for formal study in the year to December 2012, compared with 232,000 the previous year. The number of visas issued fell 4% to 501,840 in the year ending June 2013, however, this was slightly up on the 499,641 visas issued in the year ending March 2013. Within the figures, this included 204,469 visas issued for the purpose of study, a fall of 5%. And 179,000 people migrated to the UK for work, which was down from 184,000 in the previous year.

Elsewhere, a separate batch of statistics from the ONS revealed, in 2012, one in eight or 12.4% of the resident population of the UK were born abroad, compared with one in 11 or 8.9% in 2004. And in the same period, one in 13 or 7.8% of the resident population of the UK had non-British nationality, compared with one in 20 or 5.0% in 2004. India was the most common non-UK country of birth in 2012, with 729,000 residents of the UK born in India, while Polish was the most common non-British nationality in 2012, with 700,000 residents of the UK having Polish nationality. And in another pack of data, the ONS reveals a quarter of births - 25.9% - in 2012 were to mothers born outside the UK which was a slight increase from 25.5% in 2011. Poland remains the most common country of birth for non-UK born mothers in 2012, while Romania moved into the top 10 most common countries of birth for non-UK born mothers in 2012, replacing China. Pakistan remains the most common country of birth for non-UK born fathers in 2012.