Not any old piano: Dancing dons, a jolly tramp and a magic piano - all you need for a great British musical. Edward Seckerson celebrates 40 years of Salad Days

Forty years ago today, a funny little show called Salad Days came down from Bristol and slipped almost unnoticed into the Vaudeville Theatre, London. Nobody expected it to stay. And stay. Six years later, it became the longest running British musical in history. And it held on to that record until Lionel Bart's Oliver] came along, on cue, in 1960.

Salad Days was the unlikeliest of hits in a West End dominated by American blockbusters. It was one step up from revue, the flimsiest piece of summer madness involving dancing dons, titled undergrads (Evelyn Waugh revisited), a vindictive Minister of Pleasure and Pastime (David Mellor without the jokes), a comedy tramp (these were prophetic times), Uncle Zed and his flying saucer (very prophetic times), and - oh, yes, I almost forgot - a piano called Minnie which made people dance. Would you have invested in it?

The lady behind the bar at the Theatre Royal, Bristol, came up with the title. She'd been selling programmes during the run of Antony and Cleopatra and was particularly taken by the line 'My salad days, when I was green in judgement'. So when Denis Carey, director of the Bristol Old Vic, was sat at the bar with Julian Slade and Dorothy Reynolds, the composer and lyricist, wondering what on earth they might call their summer show, her moment came. Salad Days posters went up all over Bristol before a word or a note had been written.

That was February 1954. They were due to open on 1 May. But then, in those days, theatre folk worked on their feet. It was generally a case of get it down, get it on. And Slade and Reynolds did, the curtain going up as scheduled on their lusty opener 'The Things That Are Done by a Don', a number so 'far back' there really wasn't any farther to go. But it was pukka - like everything else in the show. A synopsis of the plot on the original cast album (just reissued on CD by Sony) speaks of 'a future as gay as the past'. Well, yes . . .

So, 40 years on, where stands Salad Days now? Tomorrow night on Radio 2 for starters. In a unique three-way production deal, fronted by the aptly named independent company Unique Broadcasting, a starry new recording has been licensed to EMI Records and the BBC: EMI puts out an album of the songs, the BBC a 75-minute version with dialogue to slot into its ongoing series of great musicals.

Back in April of this year, the old Beatles studio at Abbey Road was jumping to rather different tunes. Different, but no less venerable. First to catch the ear was the forgotten sound of two pianos, string bass, and drums. The Lyons Corner House sound. Three producers were crammed into the tiny control room (one for EMI, two for the BBC). Music director John Owen Edwards was on the studio floor coaxing Josephine Tewson, Timothy West and Prunella Scales through the first number of the day. The Wests were taking their singing obligations frightfully seriously: 'That's a relief, darling,' exclaimed Prunella Scales. 'I didn't think we were allowed to breathe there . . . I hope to God it sounds better where you are than it does down here.' Owen Edwards, meanwhile, was sorting out piano embellishments with Jonathan Cohen and Mark Dorrell: 'Too twinkly, Cohen - too Welsh - less lace-work please]' Such was the rush to get the original show on, the second piano part had never been written down. And then there was the little matter of Minnie, the magic piano. Mrs Mills' old upright (remember her?) was making a timely comeback.

You don't mess with the sound of Salad Days. A few added strings would totally alter the complexion - Palm Court as opposed to the piano-led spirit of revue. One revival even tried spicing up the arrangements with a touch of - hell's teeth - synthesiser.

'The whole point,' says Owen Edwards, 'is that it's a period piece. You have to be true to that. I'm actually being quite ruthless about things like rhythm and rubato. Jazz up the rhythm even a little and you throw off balance the relaxed way in which the tunes just kind of trip off the keys. Often the tiniest rubatos can sound out of character. The piano, bass and drums combination magnifies everything. It's infinitely more challenging than with a symphony orchestra. And, of course, there's always the temptation to ever so slightly camp it up. That's a huge mistake. Its charm is actually very fragile.' Simon Green, who plays Timothy, the juve lead, agrees: 'Sure it's twee, it's breathtakingly elitist. But you have to treat it like Chekhov.'

Salad Days was a last bastion of cheeriness before the advance of the kitchen sink. A fond farewell to the age of innocence. Beyond that, nobody really knows why it succeeded, save that it was jolly silly and eminently hummable. Julian Slade, the composer, a gracious, retiring gentleman, remains nonplussed: 'I suppose it made a nice change,' he says, with an understatement worthy of Alan Bennett. 'I know we set out to write a summery show about Youth. Timothy and Jane were, if you like, the first drop-outs: he didn't want a respectable job, she didn't want a suitable marriage.'

Youth culture, the generation gap, pre-Grease, pre-Hair. There's food for thought - if only a mouthful. Owen Edwards thinks the secret of its success undoubtedly lies with its origins in revue. 'That's something the British revered, something the Americans didn't have. They had vaudeville, which was a lot broader and a lot more, well, vulgar. Our revues were pithier, more sophisticated, more intimate. So the success of Salad Days may also have been a reaction against all the big, splashy American musicals that were coming across at the time.'

Which in turn might explain why the other big British musical success of 1954 - Sandy Wilson's The Boy Friend - didn't steal the Salad Days thunder, despite opening a mere three or four months earlier. 'The Boy Friend paved the way,' says Slade, 'but there was room for both of us.' Certainly was. The great British musical had arrived - with a message: you didn't need a big cast, a big band, a score by Rodgers and Hammerstein, and a bunch of over-sexed cowboys from Oklahoma to wow them in the West End.

Slade still writes. He has a finished show waiting in the wings. He hasn't moved with the times. But he's receptive to those who have - a dedicated follower of musical theatre fashion. He learnt to be infectious from Arthur Sullivan, elegance came courtesy of the Ivor Novello / Vivian Ellis school of enchantment. Ellis's Bless the Bride was the show that really turned his head. And ballads like 'I Sit in the Sun' and 'The Time of My Life' from Salad Days are of that lineage, the kind of tunes that should always be sung from faded copies. Janie Dee sings them this time around. Her predecessor, Eleanor Drew, the only trained singer in the original Salad Days company (she co-starred with Howard - then Harold - Keel in Oklahoma] at Drury Lane in 1947), now runs a hotel in Wales.

Meanwhile, back at Abbey Road, Roy Hudd welcomes us to the Cleopatra Nightclub. Asphinxia (Lynda Baron) is ready for her big 'turn' - 'Sand in My Eyes' - which producer Adrian Edwards describes as Slade's Harold Arlen number. Baron simpers and sighs, bumps and grinds: 'Shatter me, batter me, break my anatomy]' What's this, a sneak preview of the permissive Sixties? Even Salad Days had its eyes and ears on the future. Then again, in the words of another song: 'We Said We Wouldn't Look Back'. But we do.

(Photograph omitted)