Collusion of the worst kind was at work in the Robert Hamill case, the public inquiry into the Portadown Catholic's murder has been told.

A lawyer for Mr Hamill's family castigated the RUC over the investigation into an alleged tip-off of a murder suspect by a police officer.

In his closing submission to the long-running inquiry, Barra McGrory QC levelled accusations of delay and inaction in the tip-off probe.

He said there had been a “do nothing” approach by a senior detective and “collusion in its worst form” which had corrupted the force.

Lawyers for the police and for individual officers and ex-officers will make closing statements in coming days, defending their actions in the case.

Mr Hamill died from head injuries sustained in a sectarian assault in Portadown town centre in April 1997.

Mr McGrory yesterday outlined a number of the Hamill's family's chief conclusions from the inquiry evidence.

A central issue has concerned an alleged tip-off by Reserve Constable Robert Atkinson to a suspect, Allister Hanvey. The Belfast-based inquiry has heard claims that Mr Atkinson phoned Mr Hanvey’s home on the morning after the attack to warn him to destroy clothes he had been wearing. Mr Atkinson, who is no longer a police officer, denies the allegation and his legal team will be among those making closing submissions. Mr Hanvey denies any involvement in the Hamill murder.

Mr McGrory claimed there had been “collusion” between Mr Atkinson and the senior detective who headed the murder investigation, the late Detective Chief Superintendent Maynard McBurney.

The QC said this did not necessarily involve a personal connection. He claimed Mr McBurney would have known the “serious ramifications” of exposing the tip-off.

DCS McBurney “knew the enormity of what had been done by Atkinson and he knew the enormity of revealing what had been done by Atkinson”, he added. The fatal attack on Mr Hamill occurred yards from where a police Land Rover was parked with four officers on board.

Mr McGrory said the four officers — who included Reserve Constable Atkinson — “took their eye off the ball in a very significant way”.

The QC told the inquiry that police in the Land Rover had been given a “clear warning” from a member of the public that trouble was looming. They not only ignored it, but instead engaged in “casual conversation” and “banter” at the rear of the vehicle with two “trouble-making Protestants”.

It was during this conversation that the events that led to the fatal attack on Mr Hamill began to unfold, he said.