"For a second, I thought it would split open and the remains tumble out. Thank God that didn't happen, but it was one of the most brutal assaults I've ever witnessed."

The police wanted to arrest a gunman who had just fired shots over the coffins of Derry IRA men, Paddy Deery and Eddie McSheffrey.

"They baton-charged mourners. They fired plastic bullets randomly. I remember looking at women's and children's shoes scattered across the road . . . they'd come off as people fled in terror. That happened 19 years ago, but it's as vivid for me as if it were yesterday. I could never back the police, " says O'Neill.

The Sinn Fein ard chomhairle is preparing to call a special ardfheis where it will recommend supporting the Police Service of Northern Ireland (PSNI). It's hugely divisive among republican grassroots. The leadership is expected to win the vote, but there will be resignations.

O'Neill, an ex-IRA prisoner, says: "Police tore nationalist homes apart in raids. I was physically and mentally tortured in Castlereagh, so were hundreds of others. Some were beaten so badly, they were left deaf.

"Those detectives are still there, some have even been promoted. The PSNI isn't entirely different from the RUC. Look at the Omagh bomb trial and see what they've been up to."

O'Neill denies he is demonising every officer.

"I'm not saying there are no good people in the PSNI. But what they are like personally is irrelevant. I'm a republican and they're enforcing British rule in Ireland.

"It's irrelevant if more Catholics join. I don't want to be policed by a Protestant British police officer or a Catholic British police officer." Does he regard police as 'legitimate targets'? "Anyone upholding British rule in Ireland should be challenged."

Peter Sheridan wasn't thinking of upholding British rule in Ireland when, as a 16-year-old Enniskillen Catholic, he joined the RUC. "The only time the Troubles had impacted on my life was when a schoolfriend's uncle was shot dead on Bloody Sunday. I thought that a huge injustice.

"I knew nothing about politics. I was more interested in football. I just wanted to be a policeman. I applied to the RUC, the guards and the Metropolitan police. The RUC wrote back first, the Met a year later, and I'm still waiting to hear from the guards."

Thirty years on, Assistant Chief Constable Sheridan is the most senior Catholic in the PSNI:

"I was called an Orange bastard plenty of times on the streets. I remember a fellow at a checkpoint, who refused to speak English, being very surprised when I answered him in Irish, courtesy of summers in the Gaeltacht."

The dangers never bothered Sheridan, who spent many years in Derry: "There were threats.

I had to move house a few times and, ok, I couldn't drink in the Bogside Inn. But I still went for weekends in Dublin and Donegal. I still went to mass, although I couldn't be too visible at church, or do readings and other things I'd have liked to do."

Did he experience sectarianism in the police? :

"Yes, I did. There were a few bad apples in the barrel. Some sectarianism was inevitable, because the RUC, as an organisation, was 90% Protestant. Any sectarianism wasn't institutional, it was from individuals.

"It was things like whole areas being demonised because of the attitudes of a few people in them.

Everybody in an entire community being treated as suspect. Sometimes, less than nice language was used."

Occasionally, he was unhappy about how people were treated at checkpoints. "I came across bigots in the police, but it was on a very small scale.

The vast majority of officers were decent people."

Sheridan says Sinn Fein must support the PSNI: "Who else will deal with the £18m of drugs coming into Northern Ireland, the 300 rapes every year, the attacks on the elderly?

"As a society, we can either go over all the wrongs we did to each other in the past, or we can move into the future. There are people in the republican community who will never change their minds, who live with their memories and refuse to recognise things have changed.

"I would say to Sinn Fein to make decisions on the present, not the past. The PSNI isn't perfect.

The vast majority of officers are honourable people, but I'm not naive enough to believe there aren't some criminals or bigots in this organisation. Police reflect the community they come from.

"The test is how the system deals with problems.

We have accountability. If republicans came into policing, they'd be surprised at what they found."

Paul O'Connor of Derry's Pat Finucane Centre says nationalists are still hurt and angry about RUC actions. The centre deals with 120 families whose loved ones were killed or injured by the security forces.

"The police were guilty of torture and collusion.

It wasn't a mistake, it was deliberate wrongdoing. A big problem is that there has never been any public admission of that, " says O'Connor.

"There have been many positive changes to policing, but areas of concern still exist. The police have more lethal weapons now than ever . . .

new plastic bullets, CS spray, water cannons and they want Tasers. CS spray was used on a man in Rossville Street who was already handcuffed.

His face was badly burned."

O'Connor says Sinn Fein shouldn't be rushed on policing. "It's more important to get it right. The Pat Finucane Centre doesn't tell young people to join the police or not. But we would say attacks on the family homes of Catholics who do so is wrong."

Ryan Agnew (26) from Ballymena, whose father is in Sinn Fein, says the party's imminent endorsement of the PSNI has made it "the butt of jokes" among young republicans in the town. "The PSNI asked a Shinner for his name the other day. The Shinner refused to give it. One of my friends said to him, 'you'll be giving it soon enough to get your pay packet'."

Agnew says endorsing the PSNI will open up a huge gap between Sinn Fein and republican youth when a house is raided or there is a street confrontation with police.

"Sinn Fein will be invaluable to the PSNI because it has so much information on republicans. No one should be surprised that it will pass that on. Historically, former republicans have proved themselves more than capable of hunting down old comrades. Just look at de Va l e ra ."

Sympathy for the problems Sinn Fein is experiencing with its grassroots over policing is thin in the SDLP. "The nationalist community is crying out for policing. The old person frightened when they hear noises at night should feel free to call police, so I'm glad Sinn Fein seems ready to sign up to policing, " says Derry SDLP councillor Gerard Diver.

"But let's remember, they called us collaborators for doing so a few years ago. We've fought hard for changes to police, we've done all the heavy lifting, they're just joining in the swansong.

The best artist's impression of a future Sinn Fein policy is a current SDLP one."

Fr Aidan Troy is no stranger to the policing question. He stood with the Holy Cross children as they endured a three-month loyalist picket on their walk to school in 2001. He says the time is right to accept policing. Last week, a parishioner, James Flanagan (17), was injured in a Continuity IRA punishment attack.

"He was shot in the back, the legs, and brain.

He's lying in hospital dosed with morphine. His psychological wounds are even greater, " says Troy. "Our choice is either this inhumanity or to accept policing despite its deficiencies.

"When people highlight the PSNI's faults, I say 'have you read the Morris report?' Policing is far from perfect in the South, and we've the advantage of a strong, fearless Police Ombudsman up here and a very active Policing Board.

"Every society has policing problems. I was in the US when that awful video was played of Los Angeles police beating blacks to a pulp. It's as unfair blaming every PSNI officer for what some police did in the past, as it is blaming every priest for wrongs some priests committed."

'IRA/Sinn Fein traitors' says the graffiti on Sinn Fein offices on Belfast's Lower Ormeau Road. Local resident Sean McCaughey says most people don't accept police have changed . . .

"it's a case of new day, same sh*t".

People are sick of "Sinn Fein spin" on policing, he says, and don't believe any grassroots consultation will be genuine. If Sinn Fein supports the PSNI, McCaughey will never vote for it again: "It's not a case of a few rotten apples in the PSNI, the whole orchard is wrong. Bringing in a few Catholics, a few women, and a few gays isn't enough. We need root-and-branch change.

"The police have always used their guns against this community, they've never protected us. You should teach your kids to run to police and away from strangers. My kids do the opposite."