Northern Ireland is the UK's back door for illegal immigrants
Rise in offenders caught sneaking in through Ulster
Growing numbers of illegal immigrants are being caught using Northern Ireland as a back door entry point to the UK, according to a new report.
Over 100 offenders have been apprehended at Scottish and Northern Irish ferry terminals during the first four months of 2011 - a 65% rise on last year's figures.
Experts believe migrants are shunning the traditional cross-Channel route into the UK, with the Irish Sea now the main gateway.
There are 28 sailings a day between the Northern Ireland ports of Belfast and Larne and Stranraer and Cairnryan in Scotland, with approximately 1.8 million passengers and 750,000 vehicles using the routes every year.
The apparent rise in illegal immigration through Scottish ports follows a furious row over a decision by the UK Border Agency to axe funding for policing at the sites last year.
At the same time, responsibility for identifying illegal immigrants was transferred to a specialist team in Northern Ireland.
A report into the move reveals that 102 offenders were detected at Scottish and Northern Irish ports between January and April - up 65% compared with the same period in 2010. And critics claim the rise is evidence that people are exploiting lax security at Scottish terminals
Andy Friend from the ISU, the union for the border agency, said travelling via Northern Ireland and Scotland was now a "recognised" trafficking route.
He said the Common Travel Area agreement - which means passports do not have to be shown at borders with Northern Ireland or Scotland - makes it easier for offenders to slip through.
However, Phil Taylor, regional director of the Border Agency in Scotland and Northern Ireland, said it was because staff were becoming more effective at detecting offenders.
"We are pleased that the new system of working has resulted in a marked increase in the detection of immigration offenders, with significant numbers of these cases being detected in Northern Ireland since the transfer of responsibility," he said.
"Our enforcement team in Northern Ireland is becoming increasingly effective in dealing with this problem, adding to the success they already have at airports in the province."
The Common Travel Area agreement makes it simpler for illegal immigrants to access the UK. Under the agreement, passports do not have to be shown at borders with Northern Ireland or Scotland.
An offender can travel from France to the Irish Republic via ferry, before taking a bus across the border to Larne and then the ferry to Stranraer.