A lifelong Arsenal fan who suffered a bruised nose after headbutting pundit Roy Keane at the Emirates will not be allowed to watch football matches in stadiums for three years.

“Senseless” Scott Law, 43, clashed with the so-called “hard man of football” outside the ground’s TV studio.

The civil engineer told reporters he plans to appeal against his conviction.

During the trial, Law said his season ticket was his “prized possession” and admitted that his wife must organise her diary around Arsenal fixtures.

His defence lawyer Charles Sherrard KC said not being able to watch the Gunners for several years would be the “biggest punishment of all” for his football-mad client.

The fracas began when Mr Keane and fellow Sky Sports pundit Micah Richards were walking to do the final match analysis after Arsenal’s 3-1 victory over Manchester United, the trial at Highbury Corner Magistrates’ Court heard.

The ex-Ireland international was headbutted through doors by Law, of Waltham Abbey, Essex.

Law’s defence team claimed Mr Keane was captured on camera using “gratuitous violence” against Law by “smashing his nose” with his elbow.

But a judge ruled Law had been “untruthful about what happened”, and issued him a three-year football banning order.

Mr Keane “was calm and not agitated” when he left the studio, District Judge Angus Hamilton said.

The judge said Mr Keane’s reputation as the so-called “hard man of football” was “years ago, and was confined to the football pitch”.

“I’m sure Mr Law assaulted Mr Keane,” he added.

Mr Keane was left “in shock” by the assault, he told the court.

Giving evidence, the 52-year-old said: “I was just walking and, before I knew it, I was hit. I felt the contact and fell back through some doors.

“I was absolutely not expecting it. The only way I can describe it is that I was in shock. I didn’t expect it to happen, not when I was in my workplace.”

He said he suffered bruising on his chest and arms as a result of the incident.

Former Manchester City defender Mr Richards said he “grappled” with Law following the incident.

The 35-year-old was in “disbelief” at what he witnessed, and “felt sorry for Roy” who he described as a friend.

Law, who was sat beneath the Sky Sports studio during the match, claimed Mr Keane had been “very animated” and “angry” throughout the game.

He said he went inside the stadium to go to the toilet when he encountered Mr Keane who “collided into him”.

Prosecutor Simon Jones KC asked Law: “Are you seriously saying that Roy Keane ran into the top of your head?”

Law, who cried while being questioned, said: “I put my head down in a defensive manner to protect my face.”

As well as being barred from attending football matches, Law was ordered to complete 80 hours of unpaid work, and must pay legal costs of £650 plus a victim surcharge of £114.

Kevin Christie, Crown Prosecution Service London North football lead prosecutor, said: “This gratuitous and senseless act of violence was completely unacceptable.

“When anyone attends a football match, either to work or to support a team, they should be able to feel safe and secure in that environment.”

Reading a statement on behalf of Law outside court, his defence lawyer said: “I was found guilty by a judge who excluded me at times from my own trial.

“The prosecution deprived me of key footage for my defence.

“I most definitely plan to appeal this conviction. I will not be making any further statements.”