A man who tried to carry a pipe bomb onto a plane in his hand luggage was initially released after "errors" in the assessment of the device, police have said.

Nadeem Muhammad, 43, was planning to board a Ryanair flight to Italy on January 30 when security officers at Manchester Airport uncovered the device, made of masking tape, batteries, the tube of a marker pen, pins and wires, in the zip lining of his small green suitcase.

On Tuesday, he was found guilty at Manchester Crown Court of possession of explosives with intent to endanger life or property.

The court heard airport security had initially believed the bomb was not viable and, after being questioned by counter terrorism officers, Muhammad, who was born in Pakistan but had an Italian passport, was released.

He was able to board a flight to Italy five days later.

Superintendent Graeme Openshaw of Greater Manchester Police's Specialist Operations unit said: "Based on the overall circumstances of his stop and the information presented at the time, police officers determined that there was not sufficient evidence or suspicion to arrest the man and place restrictions on his movement.

"Following subsequent forensic examination of the device carried out by police, it was determined that it could be viable and the man was arrested at the first opportunity.

"We accept that there were some errors with our assessment of the device on the day and we have already reviewed our practices, however this incident has demonstrated the effectiveness of the airport security checks where the item was successfully detected and the passenger intercepted."

Mr Openshaw said it was unclear what damage would have been done if the bomb had been detonated once Muhammad was on board the Boeing 737.

He added: "Immediately following the incident, we have reviewed the way we respond to suspicious items found during the security process and a number of changes have been made.

"The enhanced protocols have been successfully tested on a number of occasions in the last few months."

The court heard airport security officers had swabbed the device after it was detected when the bag went through X-ray scanners, but had found no trace of explosives.

Terminal three security manager Deborah Jeffrey initially put the pipe bomb, which contained nitroglycerin and nitrocellulose, into her pocket before passing it to police.

A spokesman for Manchester Airport said: "We are proud of the work that our teams do to ensure the safety and security of passengers. In this instance, the actions of our security team led to the detection of a suspicious device.

"Following its detection, our team handed the passenger and the device over to the police to investigate further. These actions prevented a potentially dangerous item from being taken on board an aircraft."

Muhammad, of Tinline Street, Bury, told the court he had not seen the device before it was discovered in his bag and it had "nothing at all" to do with him.

The jury had been told there was no evidence of a motive or that the incident was linked to terrorism.

The businessman sobbed in court as the verdict was announced.

The device was forensically examined by police on February 8 - three days after Muhammad had flown out of the country - and the bomb squad was called after it was found to be suspicious.

Explosives expert Lorna Philp said the bomb would have had the potential to cause injury to people and damage to property if detonated, although it would have been "unpredictable".

Muhammad was questioned by police in Italy on February 9 but was released again.

On February 12, he flew back to the UK and was arrested when he arrived at Manchester Airport.

The jury spent 15 hours and 45 minutes deliberating before finding Muhammad guilty of the charge by a majority of 10 to two.

Sue Hemming, head of the special crime and counter terrorism division in the Crown Prosecution Service (CPS), said: "Despite extensive investigation, Nadeem Muhammad's motive for attempting to take this device onto a plane remains unknown.

"However, it is clear that the consequences, had he been successful, could have been disastrous."

Muhammad was remanded in custody ahead of his sentencing on August 23.