Tony Banks's relatives told of their devastation at the acquittal of the man who knifed him to death in self-defence.

His brother John and sister Lisa believe the 43-year-old was portrayed as a crazed attacker high on drink and drugs.

They claim the Crown Prosecution Service (CPS) ignored the family before and during the trial, in which builder David Armstrong, 39, of Mill Road, Lewes, was cleared of murder.

Mr Banks died on December 15 last year after angrily confronting Mr Armstrong over the affair with his wife Barbara.

The father and grandfather was drunk and on prescription pills when he tried to force his way into the ground-floor flat the lovers were sharing.

Mr Armstrong claimed to have been in fear of his life and stabbed Mr Banks five times in the head and neck with a 12in kitchen knife.

He told police: "He tried to get in through the window. He had a knife. I just panicked. I picked up the knife. I didn't mean to hurt him. I just wanted to prod him out of the window.

"There was no strength to it. It was just to get him out of the house until the police arrived."

The Banks family was stunned when, after deliberating for five-and-a-half-hours, the jury acquitted him of murder and the alternative charge of manslaughter.

John Banks, 50, said: "Tony's name was run through the mud. We accept the night Tony died he was angry and confrontational but at the trial it sounded like he was like that all the time."

Mr Banks's sister Lisa Collins, 42, who lives in Hertfordshire, said: "Tony was a truly lovely person. He lived for his family."

Detective Chief Inspector Graham Pratt, the officer in charge of the case, sympathised with the family but said the force had done all it could.

He said: "I can understand why the family were disappointed with the verdict but it was always going to be a jury decision and I accept it."

Gary Perry, head of the trial unit at Sussex CPS, said he would respond to any complaints the Banks family wished to make.

He added: "The case was presented properly by an extremely experienced Queen's Counsel.

"The fact the case got to the jury shows the case was put properly and fully by the prosecution.

"There are times when juries come to a decision that either the victim or the defendant is not happy with but that is the nature of the system."