The original idea: Who doesn’t love Beverly Hills Cop? It’s as close as the Simpson/Bruckheimer/Eisner ’80s juggernaut came to movie perfection – 105 minutes of wisecracking, smart-mouthed banana-in-the-tailpipe mayhem, with belly laughs and weapons-grade synthesisers. Audiences lapped it up to the tune of $316m (or about $644m in today’s money). That we know. What’s less well known is that it was all nearly very different. After Mickey Rourke turned the part down, Eddie Murphy’s Alex Foley was going to be Sylvester Stallone’s Cobretti – an East Coast detective marked out as a whole different kind of cop by his tight-fit tees, Wham shades and a machine gun that looked like it had been specially made for him by Black And Decker. And that tooth pick. This was a cop who meant business. He was nonchalant. He was cool. He had no food between his teeth.

What went wrong? Cobretti’s shoot first, ask questions shoot again policy was all set to unleash a shitstorm of carnage on LA the like of which wouldn’t be seen again until the bit of T2: Judgment Day when the entire place melts. Sadly for everyone except its inhabitants, Paramount took a look at the figures and realised they couldn’t afford to destroy a whole city. Stallone and homicidal mania were out, Eddie Murphy and jokes were in.

How much do we want to see this movie? Stallone’s Beverly Hills Cop is no laughing matter. As the man himself has admitted, his rewrites of Danilo Bach and Daniel Petrie Jr.’s script took the story of a Detroit detective on the tail of some serious white-collar slime and turned it into the opening of Saving Private Ryan. No-one knows if this stretched to bangalore torpedos down Rodeo Drive, but it spelt curtains for Billy Rosewood (‘Siddons’ in an early draft), bumped off at the midpoint. Michael Tandino, meanwhile, swapped from childhood friend to brother, giving Cobretti reason to unleash supplementary whoop-ass. In place of the mansion shoot-out there was a colossal car chase involving a Lamborghini, a Pontiac and, in a unfortunate twist for Victor Maitland, an oncoming train. This would clearly have been awesome. The bean-counters thought otherwise. Eight weeks before the shoot was due to start, Murphy, Reinhold and co. were on board, the script was re-funnied, and Stallone and his avenging-cop-lunatic were bundled off to killing fields new. And the rest was Cobra.

Nods to the original casting? No, but in one of the great in-jokes, posters of Cobra and Rambo adorns Billy Rosewood’s room in Beverly Hills Cop 2.