The credibility of a key prosecution witness in the trial of a restaurant manager charged with manslaughter was called into doubt yesterday -- after he admitted being drunk during the incident.

Construction worker Nick McGavern was giving evidence in the trial of Flanagan's bar employee Kevin Pollock, who is charged with manslaughter following the death of Mr. McGavern's father, Craig, outside the bar one night last July.

Mr. McGavern died from a fractured skull after falling down a flight of stairs leading to the restaurant. The Crown alleges that he was pushed by Pollock.

Nick McGavern had been on a drinking binge with his father on the night of the incident and had already been escorted from the premises earlier in the evening.

When cross examined by defence attorney Mark Pettingill, Mr. McGavern, who claimed he was standing at the bottom of the staircase in the Emporium building at the time of the incident, explained how he clearly saw Pollock shove him down the stairs.

"He flew down the stairs, so great was the force,'' Mr. McGavern said.

"Kevin was standing at the top of the stairs smiling. I was screaming at him, saying, `I saw that -- I'm going to sue your a**, I'm going to sue your a**'''.

But when further questioned Mr. McGavern, who earlier said that he had drunk about a dozen beers before the incident, admitted to suffering from blackouts when drunk.

When Mr. Pettingill asked if he could remember being thrown out of another bar, Docksiders, earlier in the evening he admitted that he could not even remember visiting the establishment.

And when asked if he could remember being escorted from the Flanagan's bar earlier in the evening by Police he said: "I cannot recall that''.

When asked if he was standing in a different location to where he claimed when his father fell he replied: "Maybe''.

And he also admitted that he could not remember anyone giving first aid to his father immediately after the fatal incident.

"You had a lot to drink and don't even remember going to Docksiders,'' Mr.

Pettingill said.

"You don't remember large parts of the first incident at Flanagan's and you don't remember the events of his treatment afterwards.

"But you want the jury to accept that you recall in some detail the events leading up to and the actual fall of your father.

"I am going to suggest to you that you were told a lot of things afterwards about this incident and your evidence is based for the large part not on what you remember but on what you were told.'' But two further prosecution witnesses were then called to give evidence and both backed up Mr. McGavern's version of events.

Sylvia Selby and her daughter Jill were both drinking at the bar when Mr.

McGavern fell.

"When they reached the top of the stairs Craig paused and leaned against the railing,'' Jill Selby said.

"At that point there was a few seconds of nothing and then I saw Kevin rush from behind and sort of push Craig and Craig just sort of flew down the stairs. It was a running force, Kevin had been standing about five or six feet behind him.'' Ms Selby's mother, although a little confused as to the exact positioning of the two parties, also claimed she saw Pollock push Mr.

McGavern.

"Mr. McGavern was leaning on a railing facing down the stairs,'' she said.

"Kevin was behind and to one side. I saw Kevin push him down the stairs.

There were about two other people with Kevin at the top of the stairs and suddenly there was this big push. I would say Mr. McGavern flew down the stairs.'' Both witnesses denied suggestions by Mr. Pettingill that the victim had acted aggressively towards Pollock just before the fall.

The case continues today.