A student who hacked into Facebook in the "most extensive and grave" case of social media hacking to come before a British court has been jailed for eight months.

Glenn Mangham, 26, admitted infiltrating the website from his bedroom in his parents' house between April and May last year. His actions were said to have risked destroying "the whole enterprise" and sparked fears among American authorities of industrial espionage.

Mangham, a software development student from Cornlands Road, York, had previously shown the search engine Yahoo how it could improve its security and said he wanted to do the same for Facebook.

But prosecutor Sandip Patel rejected his claims, saying: "He acted with determination, undoubted ingenuity and it was sophisticated, it was calculating."

Facebook spent 200,000 US dollars (£126,400) dealing with Mangham's crime, which triggered a "concerted, time-consuming and costly investigation" by the FBI and British law enforcement.

"He said he wanted a mini project and chose Facebook because of its high-profile internet presence," Mr Patel said. "The prosecution does not accept that the defendant's actions were anything other than malicious."

He told Southwark Crown Court in London how Mangham had "unlawfully accessed and hacked into the social media website Facebook and its computers in April to May last year from his bedroom in Yorkshire" and had ultimately stolen "invaluable" intellectual property, which he downloaded on to an external hard drive.

He added: "This represents the most extensive and grave incident of social media hacking to be brought before the British courts."

Passing sentence, Judge Alistair McCreath told Mangham his actions were not harmless and had "real consequences and very serious potential consequences," which could have been "utterly disastrous" for Facebook.

"You and others who are tempted to act as you did really must understand how serious this is," he said. "The creation of that risk, the extent of that risk and the cost of putting it right mean at the end of it all I'm afraid a prison sentence is inevitable."