Steven Gerrard sits down knowing it is going to be a difficult, emotional interview. He speaks as captain of Liverpool Football Club but he is here, too, as a grieving relative and it is never going to be easy opening up, or finding the words to describe something that is so deeply harrowing and involves him so personally. The past couple of weeks have brought it all flooding back but, as Gerrard says, he thinks about it every day anyway. Every time he drives into Anfield, his eyes are drawn to the Hillsborough memorial. He sees the 96 names and he knows that the youngest of them is his cousin Jon-Paul Gilhooley. "The same as me," Gerrard says, when asked to describe Jon-Paul. "A Liverpool fan from a council estate. Loved his footy, kicking around in the street. Same as me, just a year older." Jon-Paul was 10.

Twenty-three years on, Gerrard has not been able to read the report of the Hillsborough Independent Panel, and probably never will. The basic details are enough: that it was a cover-up, an orchestrated smear campaign that goes to the top of the country and constitutes a scandal of the worst form. He knows now – and this is the first point at which he lowers his eyes and his voice trails off – that South Yorkshire police tested Jon-Paul and all the other corpses for alcohol levels. But the rest? He is frightened what else he might find out. "That's the reason why I don't want to read it. It's too difficult, for my family and all the families. It's all over the papers, all over the TV. It brings it all back."

Gerrard watched the tragedy unfold on television, staring at the pictures in disbelief. He remembers the knock on the front door at half past eight the next morning and running downstairs to undo the lock. More than anything, he remembers the look on his grandfather's face as he walked through the door without saying a word. "Grandad Tony" was the first to find out. The sentence that shaped Gerrard's childhood was: "I've got bad news … Jon-Paul is dead."

Liverpool play Manchester United at Anfield on Sunday and Gerrard hopes something can change now, that the supporters of the two clubs will accept that songs about the Hillsborough and Munich tragedies go beyond the line. That is essentially why he has chosen to talk, to spread the message that it is not acceptable and to try to foster a better relationship between the clubs.

Gerrard, together with Nemanja Vidic, will release 96 red balloons before the kick-off. As captain, he will urge Luis Suárez to recognise the importance of the occasion by shaking Patrice Evra's hand and bringing some form of closure to what happened last season. "Those two players could be the key. The handshake is at the beginning of the match and they've got a responsibility to start the day off on a good note. I will speak to Suárez and my advice will be to shake hands and move on. Suárez will make his own decision. Of course he will. But I'd like to think he would want to move on himself."

There are, after all, bigger issues at play here. "I've stood on the Kop many times when it was terraced. I've been involved at games like that [Hillsborough]. It could have been me. It could have been anyone. We're talking about a disaster that puts everything else into perspective."

There are moments, such as when he contemplates that Jon-Paul would be 33 now, that Gerrard's suffering is plain to see and he nods or uses his eyes, rather than words, to express his feelings. The past fortnight has been a source of pride, vindication and relief, but never joy. "Mixed emotions, really," he says. "Delighted with the breakthrough that, at last, it's come out and that people not just in this country but around the world now know exactly how it came about. But on the other hand it brings back all the memories. When you're a Liverpool fan and Liverpool player and you've got family who were affected in the disaster it brings it all back. So sadness at the same time."

Anger, too. Does he want the people responsible punished? "I think everyone – I'm sure you are the same – does. If there are people out there who should be punished and deserve to be punished. It's not in my control. But I hope so, yes."

He is talking in a room at Liverpool's training ground where one wall carries the Johan Cruyff quote: "There's not one club in the world so united with the fans." Yet the response outside Anfield has been overwhelming, too. "Unbelievable," Gerrard says. "First and foremost, across the park, at Everton. Everyone knows the rivalry we've got. But the tribute they put on the other night [before the game against Newcastle] was fantastic.

"It's brought football together. There was a similar togetherness between Liverpool and Everton with the Rhys Jones case [the 11-year-old Everton fan who was murdered in 2007] and I think it's brilliant. It goes to show there are rivalries in football, there is banter and that football is important but that disasters and deaths do put it into perspective."

Sir Alex Ferguson has appealed for United supporters to refrain from any of the distasteful songs that have been heard from the away end at Anfield. Vidic has said the same. Sandy Busby, Sir Matt's son, too. For their part, Brendan Rodgers and various other Liverpool representatives have called for an end to chants about the Munich air disaster. "Let's have it right, it's not every supporter out there," Gerrard says. "It's a minority but people do jump on the back of it and if you're a supporter at this game and hear a whisper or someone starts making these kind of noises, then you've got a responsibility to tell the person next to you not to go down that road.

"I'm sure the Liverpool and Manchester United fans know what the right thing to do is. There's a big game of football and a lot at stake at the weekend. But this is more important than football, what we're talking about. We all love football because of these rivalries. That can't stop. But there's a line."

He does not want to preach, just make the point that maybe Liverpool and United supporters have more in common than they ordinarily care to admit. "I'm hoping human decency breaks out. It's set up for it. It's a great opportunity for both sets of fans to put the sick chants to bed on both sides. Not just because of the last couple of weeks, but because it's not right."

He is encouraged by the behaviour of Manchester City fans when they went to Old Trafford in the 50th anniversary week of the Munich disaster in 2008. "I watched that game on television. It was touching. That was good, that was nice. This is another occasion to do something similar. Alex Ferguson, Brendan Rodgers and Nemanja Vidic have all spoken about it and if I can reiterate that message, not just to the United fans but to the Liverpool fans, it would be a great occasion for that to happen.

"These are not the only two disasters that have happened. There's racism going on. There are all kinds of different chants coming from supporters which needs to stop, and if two big clubs send out the right message that it has no place in football everyone else will take note. If it's a fantastic match, there's a handshake before the game and there's no vile chanting, it will be a great advert to everyone around the world. There's going to be millions and millions of people watching this."

Liverpool's supporters will hold up coloured boards on three sides of the ground – the Anfield Road End, the Centenary Stand and the Kop – to form a mosaic spelling "96, Justice and The Truth". Ferguson and Sir Bobby Charlton will lay floral tributes. Kenny Dalglish, who worked so tirelessly to support the Hillsborough families, will be at Anfield and Gerrard knows how deeply the past two weeks will have affected the club's former manager. "It will be an emotional day for Kenny. He played a massive part in supporting all the families. It must have been a difficult 10 days for Kenny, with all the memories flooding back for him as well. But I'm sure he will be saying exactly the same thing as me. I'm sure he will looking forward to the game, hoping that it's a good game and that everyone in the crowd behaves themselves and that it is remembered for what happens on the pitch."

As for Gerrard, the task is to separate the emotions surrounding the match with the professionalism and focus that is needed once the whistle blows. "I'm fine," he says. "You focus on the game and the job you have to do. When the game starts, all the emotions of the past 10 days … you park them and try to do your job to win the game.

"It's a great opportunity for us to win our first game in the league and kickstart the season. We've been inconsistent in the opening four games – fantastic against Manchester City and Sunderland, very disappointing against West Brom and Arsenal. If we were to take maximum points, it would give us big confidence and the bit of a kickstart we need."

This, however, is far more than just an ordinary Liverpool-United fixture. "This game is about two tremendous teams. It's a big clash. It's an important game. I want to try to focus on what's going to happen on the pitch. I don't want to go into the game thinking about what Luis and Evra are going to do, or what's going to be chanted on the terraces.

"The game's on TV, everyone's waiting to see what kind of reaction it gets and it's an opportunity for the Liverpool fans and the Manchester United fans to send a message across the world that they're great sets of supporters who know this is the chance to stop that kind of chanting.

"Liverpool players and Manchester United players are not all of a sudden going to start liking each other. That's fine but we're talking about disasters that have affected both clubs. It's got to stop."