Officers from the Border and Immigration Agency, Revenue and Customs and UKVisas will be brought together to create a single checkpoint for travellers at ports and airports.

In a major security statement in the Commons, Mr Brown also announced moves for a controversial increase in the maximum time police can hold terror suspects, backing a new maximum of 56 days.

And he set out alternative proposals which would introduce French-style "examining magistrates" to run police investigations.

"To strengthen the powers and surveillance capabilities of our border guards and security officers, we will now integrate the vital work of the Border and Immigration Agency, Customs and UKVisas overseas," Mr Brown said.

"At the main points of entry to the UK we will establish a unified border force."

The Cabinet Secretary has been asked to report on plans for implementing the proposal by October and also look at whether there is a case to go further, added Mr Brown.

The new agency will be known simply as the Border Force and officers from all three organisations will wear the same uniform, a Home Office spokesman said.

Opposition leader David Cameron said he was "delighted" to see the Government adopting his party's policy for a single border force.

In a radical new move, for the first time the Government said it would be giving serious consideration to introducing a Continental-style system of investigating judges. Such a move would have dramatic implications for traditional methods of police investigation and on the way cases are prosecuted in British courts.