First shown on BBC Four, the second half of Michael Grade's history of the variety era examines what happened to the entertainers once the theatres closed and TV cameras beckoned. He talks to stars who managed to make the transition from stage to screen, among them Bruce Forsyth, Des O'Connor and Ken Dodd. Grade also looks at Sunday Night at the London Palladium, plus the impact of Tommy Cooper and Morecambe & Wise.

Enter a lost world of entertainment with this celebration of the post-war heyday of variety, in a BBC4 programme shown last month. Michael Grade is our qualified guide - he joined the family theatrical agency in 1966 - and delivers a warm and funny show, full of good anecdotes. That's because he lets veteran entertainers and agents do much of the talking - Val Doonican, Bruce Forsyth, Ken Dodd, Roy Hudd, Barry Cryer and Janet Brown among them. Although largely filmed at the London Palladium, many of their recollections concern the third rate halls, the "number threes" - Bilston Theatre Royal and Attercliffe Palace keep cropping up. They are unforgettable, but for all the wrong reasons, as are tales of theatrical digs. A parade of clips features comics, ventriloquists, dancers, jugglers and animal acts - from Max Miller to Memory Man, and Kardoma the flag act to Koringa the lady snake charmer. Nostalgia, social history, however you label it, there's nothing po-faced about this supremely entertaining show.

This two-part documentary received glowing reviews when it debuted recently on BBC Four. Lord Grade (whose various roles in broadcasting have included chairman of the BBC, chief executive of Channel 4 and executive chairman of ITV) looks back at the postwar golden age of variety theatre and meets an array of well-coiffed, cardigan-clad old school entertainers including Val Doonican, Ken Dodd, Barry Cryer, Roy Hudd and Janet Brown - whose memories of performing with Max Miller are particularly amusing. Grade is knowledgeable and passionate about his subject: his father was a theatrical agent, his uncle Lou a celebrated impresario and he spent much of his childhood roaming round music halls. The result is a warm, nostalgic elegy for a lost world - one ultimately destroyed, of course, by the very medium through which this lament is broadcast.

In part two of the terrifically enjoyable The Story of Variety, presenter Michael Grade investigated television's culpability in killing off variety, and highlighted the attempts of various performers to make the tricky transition from stage to screen.

Tommy Cooper adapted instinctively, Morecambe And Wise succeeded on their second attempt, while Ken Dodd never quite succeeded in shrinking his genius to television's proportions. Ventriloquist Peter Brough and his doll Archie enjoyed tremendous, if inexplicable, popularity on the radio, but a clip from the archive showed why they never enjoyed small-screen success - Brough had failed to grasp a fundamental element of ventriloquism and made little or no effort to disguise his moving lips.

Story of Variety review: So Seventies

Last night, I finally got round to watching Part 2 of The Story of Variety with Michael Grade. Part 1 was excellent, interesting and surprising - full of stuff about the thousands of variety acts criss-crossing Britain to play the hundreds of variety. Part 2 was a little bit rubbish and covered the well-trodden variety acts who ended up on TV.

Much as I love the story about a young Des O'Connor pretending to faint on stage at the Glasgow Empire in 1969 rather than risk further exposure to the toweringly unsentimental crowd, there's a cynical part of me which wonders if the yarn hasn't been a wee bit embroidered.

I didn't expect Michael Grade's The Story Of Variety to rubbish it, and sure enough we got the director's cut (special edition).

Des continued with the ruse backstage, said Grade, so the stage manager carted him off to Glasgow Royal Infirmary where the nurses where persuaded to wield extra-sharp scalpels. That quickly brought him round and he was back on stage for the second house.

But this was a smashing show. Hoofers and troupers and agents with great names like Dabber Davis shuffled into the warmth to reminisce about a showbiz tradition born after WW2 as a more respectable version of music hall - then killed off by TV and a desperate lurch into nudity.

Liverpool alone boasted 25 variety theatres, according to Ken Dodd, who evoked the roar of the greasepaint like this: "Lovely darkened rooms, lovely smell of oranges and cigars - then that lovely rumpty-tumpty sound." But just as many anecdotes related to life away from the proscenium arch: on the road, Aberdeen one night and Plymouth the next, never seeing home for 18 months, not actually having a fixed address, the big meet-up on the railway platforms of Crewe - the digs!

Some landladies were "Artists only - no straight people". Some put out tablecloths for actors but not for "twice-nightlies", as variety acts were known. Roy Hudd recalled the Christmas Eve he hoped for respite from what had been a tyranny of baked beans: "Beans again, but with one chipolata buried in them."

Another variety veteran, Scott Saunders, remembered a landlady who was more obliging: "I got back to the digs late and the pianist Semprini was shagging her on the kitchen table. 'Oh Mr Saunders, what must you think of me?' she said, and just carried on."

"Television's job is to leave us more alert than it found us." Yes, someone actually said that. Don't worry, it was a long time ago. The second part of this documentary focuses on the arrival of television. So many shows, particularly Sunday Night at the London Palladium, were variety shows broadcast live, so TV had an immediate and seemingly inexhaustible supply of seasoned, professional performers. But it also meant that people no longer had to go out to enjoy entertainment - and the effect on the variety theatres was devastating. Great anecdotes and clips of a long-gone era.

This second exploration of showbiz is a tale of those who could play to the camera, instead of the audience. Ken Dodd shows how he's torn between the two. Others did not face the same dilemma - witness Morecambe and Wise's mastery of the medium. For the other modern great, Tommy Cooper, we learn performances were meticulously planned. But in 1984, with alternative comedy booming, both Tommy and Eric died. But variety didn't die with them. We have Britain's Got Talent. And now ITV has bought the rights to the Royal Variety Performance. That wouldn't have happened had Grade been back at the BBC.

One episode should have been enough for this two-part documentary, which concludes by showing how television brought the demise of variety theatre and became the entertainment of choice. It's also achingly luvvie, as Grade recalls the heyday of the London Palladium ("the temple of show business") and talks to the entertainers who managed to make the transition from stage to small screen, among them Bruce Forsyth and Ken Dodd. Grade also looks at the impact of acts such as Morecambe and Wise, tells how ITV initially stole a march on the BBC in the variety stakes and gives a nod to an impresario who was a precursor to Simon Cowell.

Last Night's TV - The Story of Variety, BBC4

Nostalgia is for losers, but it often makes great telly." So began my last contribution to this page, reviewing the Imagine take on Ray Davies. Forgive me for returning to it. I know it's not the done thing to copy and paste from one's own work, but we're so much in the same territory with The Story of Variety that not doing so would be dim. And for the avoidance of doubt, here was Michael Grade, three minutes in, describing his project as a survey of a "lost world... [that is] gone but isn't quite forgotten".