The British government on Wednesday ruled out a cyberattack as the cause of a nationwide e-gate outage at a number of airports that caused long delays for passengers.

The electronic gates which scan passports and use facial recognition went down shortly before 8:00 pm (1900 GMT) on Tuesday but were up and running again shortly after midnight (2300 GMT Tuesday).

"At no point was border security compromised and there is no indication of malicious cyber activity," the Home Office said in a statement.

Earlier on Tuesday, the government said it could not rule out state involvement in a mass cyberattack on the personal details of armed force personnel, with some lawmakers blaming China.

Beijing denied that it was behind the hack on a contractor's payroll system used by the defence ministry containing the names and bank details of up to 272,000 British service personnel.

Airports including London Heathrow, London Luton, Edinburgh and Manchester saw severe delays, as Border Force officials had to manually check all passports.

Hundreds of passengers queued for over an hour at passport control at London Luton airport, according to an AFP correspondent at the scene.

Travel disruptions were reported just two weeks earlier when the same e-gate technology experienced glitches at several airports.

Rail passengers also faced delays as train drivers across services went on strike on Wednesday in a long-running pay dispute.

The latest travel chaos to hit UK transport came a week after Border Force workers staged a four-day strike at Heathrow airport over working conditions.