The case against two Canadian pilots accused of preparing to fly a passenger plane while under the influence of alcohol has collapsed after their blood samples were destroyed at a prison.

It came after the Appeal Court ruled the Crown had not met its duty to supply Jean-Francois Perreault and Imran Syed with their part of the blood sample used to test for alcohol levels.

Prosecutors said that after “full and careful consideration” of the facts and circumstances there would be no further proceedings in the case.

Mr Perreault, 41, and Mr Syed, 39, were arrested on July 18 2016 before they were due to take off on the Air Transat flight from Glasgow to Toronto.

Syed, from Toronto, was accused of performing “an activity ancillary to an aviation function” when he allegedly had 49 milligrams of alcohol in 100 millilitres of blood, more than double the legal limit of 20.

Perreault, from the province of Ontario, faced the same charge with an alleged 32 milligrams of alcohol in 100 millilitres of blood.

They had denied the charge.

The delayed Airbus flight eventually set off with a different crew the next morning, with about 250 passengers having spent the night at hotels close to Glasgow Airport.

At a previous hearing, which could not be reported until now, Paisley Sheriff Court heard that both men requested part of their blood samples when they were taken in July 2016 so that they could have them independently analysed.

The samples were among their belongings when they arrived at HMP Low Moss on July 19 2016, however prison staff did not know what to do with them.

Paul Scoular, security manager at the prison, working for the Scottish Prison Service, said he was concerned the blood samples might no longer be of any worth because they had not been in cold storage.

He discussed his concerns with the pilots and said both men gave him their consent for the samples, known as B, to be destroyed.

Mr Scoular passed the samples to the prison nurse who put them in a locked drawer and later destroyed them when she heard the two pilots had been released from the prison.

Giving evidence himself, Mr Perreault said he did not give permission for his blood sample to be destroyed.

He told the court: “I wanted to have my blood sample analysed.”

The case against the pilots was originally heard at Paisley Sheriff Court (John Linton/PA)
The case against the pilots was originally heard at Paisley Sheriff Court (John Linton/PA)

Following a hearing at Paisley Sheriff Court in September, Sheriff James Spy ruled that the samples were available for independent analysis at the time and that police and the Crown were not responsible for what happened to them later, and that the case could proceed.

However the defence appealed against his decision, arguing that the blood samples should be inadmissible as evidence.

In February the Sheriff rejected the appeal, however the case then went to the Court of Appeal in Edinburgh where the defence won their appeal, with judges saying the Sheriff ought to have ruled that sample B was not admissible.

On Thursday it was confirmed that the case has fallen.

A Crown Office spokesman said: “It is the duty of the Crown to keep cases under review. After full and careful consideration of the facts and circumstances, including the recent decision of the Court of Appeal, Crown Counsel instructed there should be no further proceedings at this time.

“We are working with Police Scotland to ensure there are proper processes and guidance in place covering the retention and storage of samples when an accused person is remanded in custody.”

Both men were suspended by Air Transat after their arrests.

A spokesman for the airline said: “We note that all charges against our pilots have been dropped. The pilots were indeed suspended pending the outcome of the court proceedings. They have now been declared innocent.

“The safety of our passengers and flight crews is our number one priority. We have always taken, and will continue to take, all necessary measures to ensure that applicable regulations, as well as our internal rules are followed to the letter. We can count on the unfailing co-operation of our personnel in that respect.

“We will be meeting with them in the next few days to plan their reinstatement since there is no charge against them and we have no evidence that they have broken any law nor our internal rules.

“They will need to undergo retraining and requalification as per applicable legislation, and we will put in place measures to ensure that their behaviour is exemplary.”