An Irishman who worked and “often shared a pint” with Derek Bird remembers the crazed gunman as always having a smile on his face.

Derek Bird shot dead 12 people and wounded 11 in the Britain’s picturesque area of the Lake District on Wednesday. The police still do not know what his motive for this mass murder was.

John Coughlan, a freelance journalist, has lived in Cumbria for 13 years having moved from County Cork. He worked alongside Bird at Sellafield nuclear plant her spoke about his horror when he learnt the identity of the vicious gunman who shot many of his victims in the face, the Irish Examiner reported.

Coughlan described his friend Bird as a mild mannered person who would always offer to buy you a pint in the local [pub].” He and his wife, Gloria, were horrified by the news.

“Derrick was a joiner then and had a taxi part time, I worked alongside him every day for 18 months. It was an unbelievable shock to my wife and family when I saw his picture on Sky News, I just couldn’t believe it, the guy was so nice and quiet.

"To talk to him you would never get the impression that he would do anything like this," John said.

He said that his family in Cork has been frantic trying to get in touch with him after Bird became randomly shooting people in the sleepy town of Whitehaven in the Lake District.

Though John was shocked that Bird would have been capable of such a horrific act he also said that he didn’t really know any details about his life. He said “Nobody knew much about him other than the fact he was divorced and into motor racing.”

"The grief and hurt and pain among the people of Cumbria is unreal as it is such a tight knit community."

Serena Simmons, a senior lecturer in psychology at Nottingham Trent University said that Bird most likely suffered from a very paranoid personality.

She said that though it seemed like a random impulsive act he could have been planning the killing spree for weeks.

“With this profile you see people who are not necessarily out of touch with reality but may have a paranoid personality,” said Simmons.

"It may not have been weeks leading up to this. The decision to do this may have been taken in days.

"He may have felt angry and frustrated and the killing was a final statement.”

Picture of Derek Bird inset, Police guard crime scene