Indian doctor Sabeel Ahmed, who was sentenced to 18 months in jail after he pleaded guilty to withholding information about his brother's suicide plot to blow up Glasgow Airport, will be deported to India immediately because of the time served on remand.

26-year-old Sabeel, who hails from Bangalore, was released Friday night into the custody of immigration services and will be voluntarily deported.

Sentencing him at the Old Bailey court in London [Images] on Friday, Justice Calvert-Smith said he accepted there was no sign of him being an extremist or party to extremist views, but observed that he should have shared his knowledge with the authorities about terror activities of his brother Kafeel Ahmed.

As an international doctor, Sabeel was on a year-long 'limited registration' with the General Medical Council, which lapsed last July.

Kafeel drove a burning Jeep Cherokee into the Glasgow terminal building on June 30 last year. He died in a hospital weeks later due to the severe burn injuries he sustained in the botched attack.

Sabeel, who worked at Halton hospital in Runcom, pleaded guilty in the court and admitted that he had failed to inform the police regarding the terrorist attack. He was arrested from Liverpool on June 30 in connection with the failed terror plot.

Sabeel told officers that his older brother Kafeel was in Iceland carrying out research on global warming, instead of admitting that he knew of his suicide mission.

He continued to mislead detectives probing the attack last June for five days. He failed to tell them that Kafeel had mailed him half an hour before driving into the airport, directing him to the 'drafts' section of an e-mail account.

When Sabeel logged in an hour after the Glasgow attack, he found his brother's suicide note and Islamic will as well as instructions to lie to police about his whereabouts.

In the e-mail, Kafeel wrote of his decision to kill himself 'for the sake of Islam' and asked his brother to maintain his cover story to 'keep me alive for as long as possible'.

He had written the message before he and his fellow plotters drove two Mercedes cars to London laden with gas cylinders, petrol and mobile phone detonators.

The following day 27-year-old Kafeel, who had a PhD in engineering, tried to ram the Jeep Cherokee through the doors of the main terminal building at Glasgow airport.

Engulfed in flames, he poured petrol over the car and threw a petrol bomb. No one lost their life in the attack except Kafeel, who suffered 90 per cent burns and succumbed to his injuries several weeks later.