Last Night's Television: Manson, FIVE<br />On Tour With The Queen, Channel 4

Forty years ago this week, Los Angeles was reeling in the wake of a crime horrifying even by the standards of that blood-splattered metropolis. Three months later, the murderers of seven people including actress Sharon Tate, the heavily pregnant 26-year-old wife of director Roman Polanski, were identified as acolytes of the sociopathic Charles Manson, members of his so-called Family, who had been acting on his addled orders with the intention of kindling a race war between blacks and whites, to which he, influenced by the Beatles, called Helter Skelter.

Most of us already knew as much about this nasty episode as we wanted to, but last night's dramatised documentary, Manson, committed another two hours to it, an exercise supposedly justified by the willingness of Linda Kasabian to tell her story for the first time.

Kasabian was an impressionable young woman escaping an unhappy marriage when Manson made her one of his Family, and on the night of the Tate murders at 10050 Cielo Drive, she acted as lookout. Later, she agreed to testify against the murderers in return for her freedom. She has stayed out of the limelight ever since, and here allowed only half of her face into the limelight, which was probably wise. For all her tissue-clutching, eye-dabbing remorse at having been an accessory to some notably gruesome murders, she still seemed deluded about the essential nature of the Manson commune.

"There was a harmony amongst all of us, and it was actually beautiful," she said, as if she were still just a little under the spell of a man who even before the Tate murders had spent more than half of his 33 years in reform schools and prison, and who had once sodomised a fellow inmate while holding a razor blade to his throat. Kasabian will have to forgive us if we struggle to see Manson, at any point in his wretched life, as the purveyor of harmony and beauty.

Still, she was there and we weren't, which is why the makers of Manson chose to go down the road of the dreaded dramatic reconstruction, to afford us some useful insight. They shouldn't have bothered. Generally speaking, re-enactments only enhance a documentary when the subject matter is beyond anybody's recall. By all means, give us men in powdered wigs discussing the Jacobite threat, but there is plenty of home-movie and newsreel footage, and personal testimony, to document the Manson story. In other words, tell us, don't show us, not least because no amount of acting can convey the crazed brutality of those killings, or the warped messiah complex of Manson himself. Dramatising the story looked tasteless, sensationalist and cheap.

There was no effort to part-dramatise On Tour with the Queen, praise be to the television gods. This is a documentary series about the epic goodwill tour of the imploding British Empire, undertaken by the new Queen Elizabeth II in 1953. Actually, there was more than goodwill at stake. A Britain struggling through post-war austerity could not afford to hold the Empire together, but by sending the 27-year-old Queen and the Duke of Edinburgh around the world to watch lots of tribal dancing, an altogether different set of movers and shakers hoped that Britain's diminishing influence in the world might be reversed.

An actor and playwright, Kwame Kwei-Armah, landed the very juicy job of following in HM's dainty footsteps, which last night took him to Bermuda, Jamaica and Tonga. Kwei-Armah is a jovial sort, and his parents came from Grenada, on the wave of immigration that followed the Queen's visit to the Caribbean, so I can see the logic of making him presenter, but he's not, alas, particularly good at it. There are trivial but inexcusable errors in his script – Southall is not "literally" a mile away from Heathrow, Jamaica is not the largest island in the Caribbean – and while it's good to see yet another round-the-world trip given a fresh face, it's hard to avoid the conclusion that we might have been better served with a few more stamps in the passports of Billy Connolly or Michael Palin, or perhaps Lenny Henry.

That said, the series has much to recommend it, principally a wealth of archive material and voiceovers that make you weep not so much for what we have lost, but for what we were like when we had it. As the Queen toured Bermuda, a commentator solemnly opined that she "needed little reservoirs of strength and composure whose depths we ordinary mortals never plumb". And there was priceless footage of 17 West Indian Prime Ministers, all in court dress, meeting her plane on the tarmac in Jamaica. The biggest treat of all, though, came from Kwei-Armah's interview with the King of Tonga, the grandson of Queen Salote, who was one of the stars of the coronation, refusing to shelter from the rain and supposedly eliciting Noël Coward's famous quip that the little man next to her was her lunch. The present King of Tonga, it emerges, has a cut-glass English accent like that of Coward himself.