Some foreign passengers landing at Heathrow's T5 have entered the UK without showing their passports it has been admitted.

According to airline British Airways (BA) the security errors - which involved a "small number" of passengers - were due to the new terminal's layout.

BA said the passengers were mistakenly treated as domestic arrivals.

But the airline says it now has new processes in place to prevent this from happening in the future.

A BA spokeswoman said: "When Terminal 5 initially opened there were a very small number of incidents where passengers from international flights were bussed to the wrong zones.

"We are confident that this matter has been addressed and new processes have been put in place."

Heathrow's T5 has been dogged by numerous problems since its opening.

Passengers faced chaos when the £4.3billion terminal opened on March 27 and its baggage handling system failed.

Hundreds of flights were cancelled and thousands of pieces of luggage remain in limbo.