KARACHI: The National Crime Agency (NCA) of the UnitedKingdom on Tuesday claimed to have seized `a quantity of heroin` on a Pakistan International Airlines aircraft afteritlanded at London`s Heathrow airport on Monday afternoon.

While the PIA said `it has not been informed either verbally or in writing by any security agency for any narcotics/ drugs on board PIA aircraf t flight PK-785 during search at Heathrow airport, the BBC Urdu reported that the NCA confirmed the seizure of heroin from the PIA aircraft in a statement sent to the media organisation.

Also on Tuesday, responding to queries about the drug seizure on Twitter, the agency said: `NCA officers are investigating following the seizure of a quantity of heroin on board a flight f rom Pakistan to the UK.

PIA spokesperson Mashhood Tajwar confirmed to Dawn that the aircraft was thoroughly searched and its crew members were detained for two hours for questioning by the British authorities.

He said the aircraft was later allowed to fly to Pakistan. The flight was operated by a fresh set of crew as per routine and it arrived at Lahore`s Allama Iqbal International Airport at around noon on Tuesday.

Giving details of the episode in London, he said soon after passengers disembarked at the airport the authorities came on board and started searching the aircraft. The crew members remained at the airport during the search and were asked a few questions. They were later allowed to proceed to their hotel.

He said the PIA crew members who had brought back the aircraft to the country were already stationed in London.

`PIA officials deputed in London are in contact with the authorities, inquiring toascertain the cause and /or reason of the security search and temporary detention of cabin crew. The passports are with the crew members who will operate their regular scheduled flight to Pakistan tomorrow [Wednesday]. All PIA flights to London are operating as per schedule.

Meanwhile, senior pilot Hamid Gardezi told reporters in London on Tuesday evening that he had no information whether any drugs had been recovered f rom the aircraf t or not.

He said the UK authorities kept the crew in isolation for five to six hours. He claimed that they were not questioned about anything, but the attitude of the UK authorities was humiliating.

He said that the aircraft was cleared by the Anti-Narcotics Force at Islamabad airport before it lef t for the UK on Monday.