Gordon Brown has assured the Rev Ian Paisley that British citizens travelling between Northern Ireland and the rest of the United Kingdom will not be subject to passport controls as a result of proposed new electronic borders.
The DUP leader had written to the British prime minister expressing unionist alarm at the possibility that an "e-border" around Britain could see British citizens in Northern Ireland uniquely required to produce identification when travelling to other parts of the UK.
In reply, Mr Brown has told Dr Paisley that "there are no plans to require domestic passengers to produce passports on any domestic air or sea journey, including on routes from Northern Ireland to the rest of the United Kingdom".
Mr Brown's letter does not address the issue of identification that could be required for passengers travelling from the North to Britain by ferry.
However, Dr Paisley appears satisfied that the proposed new security arrangements envisaged by the UK Borders Bill will see the North treated on the same basis as the rest of the UK.
In a statement issued on his behalf to The Irish Times last night, Dr Paisley - who wrote to Mr Brown in his capacity as party leader rather than as Northern Ireland's First Minister - said he was pleased Mr Brown had "so robustly defended the integrity of the United Kingdom's border".
Dr Paisley urged the Irish Government "to co-operate fully with the UK in securing our borders against those who would exploit them for criminal or terrorist ends". He added: "It is only right and proper that British citizens in Northern Ireland are treated on a par with their fellow-countrymen in the rest of the UK."
Referring to Section 14 of the Police and Justice Act 2006, which introduces a new power for the police to request passenger, crew and service "data" on domestic and sea journeys, Mr Brown confirms this power will be brought into force sometime this year, adding: "So, although passengers may be asked to prove their identity when travelling between Northern Ireland and the rest of the United Kingdom [as they do already on many flights], there is no question of instituting passport control for people travelling within the United Kingdom."
In his letter, Mr Brown confirms "there is no question of introducing fixed immigration controls on either side of the land border" between the North and the Republic. Successful joint operations between the British Border and Immigration Agency, UK police and the Garda National Immigration Bureau had successfully prevented "non-common travel area (CTA) nationals attempting to cross the boundary illegally in both directions", Mr Brown told Dr Paisley.
He pledged his commitment to continue consultation with "all common travel area interests" as part of the ongoing review of the rules and operation of the CTA.