Hundreds more foreign migrants left Ipswich than arrived last year, according to official figures released yesterday.

The Office for National Statistics said net migration in the town fell 473, while across Suffolk 1,262 more migrants left than arrived.

The data bucks the national picture which suggests 165,600 more migrants arrived than left in 2012.

Atul Hatwal, director of the Migration Matters Trust, said the decrease in net migration in Suffolk was striking.

“Although there would need to be a careful analysis to identify the cause, one potential reason could be changes in the local agricultural economy,” he said.

“East Anglia is one of the four areas in Britain (along with Kent, Herefordshishire and the east coast of Scotland) where local agriculture leans most heavily on migrant labour. Whether the fall is symptomatic of tougher times for farmers in the region, or driven by difficulties in recruiting enough workers, it could potentially have major implications for East Anglia’s economy and merits detailed analysis by the local public authorities.”

Albert Grant, founder of Ipswich and Suffolk Council for Racial Equality, said he was surprised by the figures and he had not noticed large numbers leaving and had, in fact seen many more people coming from countries in Africa, including Tanzania and Zimbabwe, and also from Afghanistan.

But he said there were many West Indians moving to London from Ipswich as they were struggling to find local jobs, which were being handed to white workers.

An Ipswich Borough Council spokesman said: “We are treating these statistics with a bit of caution as our own State of Ipswich report, based on census figures, points to a net migration increase.”

The figures come after months of debate over immigration. David Cameron visited Ipswich earlier this year to deliver a controversial keynote speech about getting tough on European migrants’ benefits.

The population statistics released yesterday showed that Suffolk’s overall population grew 2,199 in 2012, with a 8,317 births outweighing 7,041 deaths in the county.

Nationally the ONS found the UK had its biggest baby boom since 1972 as 813,200 births were recorded in the past year.

It said the birth increases were being driven by large numbers of women in their 20s and 30s who were becoming mothers, along with an increase in the number of migrant families in the UK. The number of non UK-born mothers is about 26%, the ONS said.

Overall the UK’s population has grown by more than 400,000 to 63.7 million. The growth of 419,900 in the past year means the UK has had the biggest growth of any country in Europe in the year to June 30 2013 and it is now the third largest EU nation behind Germany and France.