A North Yorkshire man has admitted making the bomb threat tweets that sparked a major security alert at a high-profile football match.

Martin Butterworth, prosecuting, said Kieran Anthony Mark Richardson referred to blowing up Portsmouth's home ground during the team's League One play-off against Sunderland.

He also made reference to the Manchester arena terrorist attack, claimed he had a ticket for the home fans enclosure and tweeted about shooting Portsmouth supporters.

York magistrates heard that Portsmouth FC arranged increased security for the game on May 16 and that some of its staff were too terrified to attend.

The serious crime unit of North Yorkshire Police tracked down and arrested the 22-year-old tweeter within hours of the tweets.

Police kept Richardson, who has previous convictions for malicious communications, in their cells until the match was over.

When he made his first court appearance, the 22-year-old of Northallerton Road, Brompton, pleaded guilty to making a malicious electronic communication on May 15.

Magistrates adjourned sentence for a pre-sentence report. He was released on bail and will return to court on July 2.

More than 18,000 people attended the match, which was a draw.

Defence solicitor James Fenny said that within minutes of making the tweets Richardson “realises what he has done and deletes it, but by then it is too late. He’s not been to a football game for many years.”

The tweets had been in response to a tweet from a Portsmouth fan.

At 3am on May 16, police arrested him and searched his house.

Richardson had not had a ticket for the game, and didn’t have weapons or explosives at his home.

He had been in trouble regularly when he was younger, but in recent years had been leading a more law-abiding life.

Sunderland won the play-off overall but were defeated in the Wembley League One final.

Both Hampshire Police and Portsmouth FC issued statements reassuring fans following the tweets.