An experienced pilot who was found to be more than three times the permitted alcohol level as he was about to fly a jetliner with 156 people on board from Leeds Bradford Airport to Pakistan has been jailed for nine months.

The judge sentencing Irfan Faiz, 55, said it was "extraordinary" that the rules in Pakistan only stated that there should be a 12-hour gap between "bottle and throttle", no matter how much the pilot had drunk.

And Mr Justice Coulson at Leeds Crown Court said he was "astonished" to hear that pilots regularly flying out of the UK were not aware of the rules in this country, which are based on the amount of alcohol present in the body.

Father-of-two Faiz was breath-tested at the airport on September 18 as he was undergoing pre-flight checks in an Airbus 310 with 145 passengers and 11 crew on board.

He was about to pilot the PIA 776 flight to Islamabad when he was asked to leave the cockpit due to concerns raised by security staff who said he smelled of drink and was unsteady on his feet.

Faiz gave an initial reading of 41 microgrammes in 100 millilitres of breath on the police officer's handheld device. The legal limit for driving a car is 35 microgrammes but for flying in the UK it just nine, the court heard.

He later gave a reading on the evidential machine of 28.

The pilot told police he had consumed three-quarters of a bottle of whisky but had stopped drinking at about 3am. He was arrested before the flight which was due to depart at 10.10pm.

Faiz admitted a charge of carrying out an ancillary aviation function while impaired by alcohol, contrary to the Railways and Transport Act 2003, at a previous hearing.