On a beautiful sunny day in suburban Bristol last April, this storm in a tabloid tea-cup was still far off. The crew had taken over a house in an elegant terrace perched on a hill overlooking the city. To turn it into Nick's house, they had strewn the sitting-room with props - a Partick Thistle hat (Nick's team) by the window, a photo of Nick and Karen on the piano. The rising voice of Peter O'Sullivan blared out of an upstairs window; the real-life owner had not needed to vacate her bedroom.
The producer, Andrew Eaton, a genial Irishman previously responsible for Roddy Doyle's Family, was overseeing a scene in which Nick collapses in the kitchen while reaching for a bag of sugar and has to be dragged away from the debris by Karen. "I've pulled a few blokes in my time, but you take the biscuit," she puffs. "I'm just playing hard to get," he rejoins.
Eaton foresaw some incoming fire. "There will always be those who get upset. Some people take offence if you say 'Christ'. When we made Family, people said it was stereotyping Irishmen. That's like saying that Alf Garnett stereotypes all Englishmen."
Eaton went on to explain why Go Now is not another "illness-of-the-month feature", as he puts it. "It is leavened by black humour - particularly in the moments of greatest stress. It is about the effect of the illness on a relationship. It's a bit like going out with someone and the woman unexpectedly gets pregnant. You think, 'What are we going to do now?' "
At the launch in a preview cinema in the West End of London this week, McGovern and Powell held court at the bar. Both bearded, fast-talking Liverpudlians, they make quite a double-act. They met at a writers' workshop in 1990, when Powell presented McGovern with his diary - the seed that flowered into Go Now five years later.
"What we wanted was a love story as opposed to a story about MS," says McGovern. "We also wanted to make it funny. We found it very difficult to get the balance right, but we're just a couple of tarts so if there was a joke to be put in, we'd put it in. There's nothing quite like a joke at a sad moment. The best jokes are at funerals."
At one point, a lad from Nick's football team asks him: "If you do end up in a wheelchair, can I have your footy boots?" Powell was a pub manager and a regular footballer and golfer before being diagnosed in 1988: "Life revolved around sport and going for a drink with the lads." Now in remission, he reckoned that writing the script was "like exorcising ghosts. The MS was there; I had no choice. What was hurting me more was the personal relationships, the way people were suddenly treating me with kid gloves. All the events in the film are based on things that really happened to me. I put words into Nick's mouth that I always wanted to say but never dared to."
He cites a particularly moving scene in which the severely disabled Nick laboriously attempts to play pool. When his mate deliberately misses a shot, Nick explodes: "Don't fucking patronise me. I want to be told to get my round in. I want a bit of stick. I want a pasting on there, 'cause I'm still the same [points to head] up there."
At the centre of the film is a characteristically mesmeric performance by Robert Carlyle as Nick. In painstaking detail, he charts the character's decline from fit athlete to a wheelchair-bound man unable to turn a tap. As Eaton points out, "Even when there's no dialogue, he's doing an awful lot."
After similarly show-stealing displays as the skinhead serial-killer in Cracker, the gay lover in Priest and the hard-nut punk in Safe, Carlyle is building an impressive portfolio of difficult-to-take characters, all of whom, including Nick, the angry, foul-mouthed and deeply sympathetic MS sufferer in Go Now, are light years away from Carlyle's happy-go-lucky bobby Hamish Macbeth.
McGovern - a great raconteur given a glass of wine, a packet of Benson & Hedges and half a chance - tells an admiring story about the amount of research Carlyle puts into his characters. When he played Albie, the psychopathic Liverpool fan in Cracker, Carlyle, a native Glaswegian, resolved to speak in a Liverpudlian accent the whole time - whether on or off camera.
"To test him out," McGovern recalls, "Ricky Tomlinson, another actor, phoned Robby up at three in the morning - and he still answered in Scouse." Shades of Robert De Niro - with whom Carlyle has been compared. (Shaving his hair and donning a combat-jacket for Cracker, Carlyle gave more than a hint of Travis Bickle.) During lunch last April, Carlyle took a well- earned break from filming, relaxing in his shades and leaning back in an armchair by the catering-bus. "These are the parts to go for. To me, the more difficult it is, the better. They bring out your darker side. It's therapeutic. If you stab someone on screen, it saves you doing it in your personal life. Your friends are glad they don't have to say, 'don't let him near our kitchen knives.'
"I'm a bit of a research maniac. For the part of Nick, I spent a long time talking to MS sufferers in Scotland. The difficulty is asking the fundamental questions - 'What did it feel like when the doctor told you?' When certain people told me, they got quite emotional."
Powell believes Carlyle's research has paid off. "He was terrific. I noticed some things that other people wouldn't - like his head movements. They were absolutely accurate. When you're walking, you have to keep your head perfectly still because if you move it to either side, you lose your balance and fall over."
Powell is now working up another, unrelated screenplay. "Maybe I'll slap a script down on a commissioning editor's desk and he'll say, 'Bloody hell, Jimmy McGovern was taking a ride all along'."
Somehow, you suspect that Jimmy McGovern is likely to survive on his own. In the wake of Cracker and after some years of relative anonymity on Brookside, he is one of the very few television writers whose name attached to a project is enough to get it green-lighted. He is planning a drama about the Hillsborough disaster and he reveals that George Faber, head of single dramas at the BBC, "is murmuring about a sequel to Go Now". He is currently working on his last ever Cracker. "I think [Robbie] Coltrane and I both feel we've gone as far as you can," said the writer. "We've already covered every perverse emotion known to man."
'Go Now' opens BBC2's 'Love Bites' series of single dramas tonight at 9.25pmReuse content