Thank heavens for Diana Rigg. It is 30 years since she last slid into Emma Peel's snug-fit leather catsuit in The Avengers. But she is still the Queen of the Cool-girl heroines. Not that there are so many of that breed around any more. Unlike America, where women seem to be able to get a fair - or even better than fair share of leading roles.
When Emma Peel struck up her partnership with Steed in the Avengers in 1965 she became an icon. It was not just because of the outfits. Leather catsuits do not an icon make. Look at Uma Thurman in The Avengers movie remake. By all accounts she exudes as much allure as Ann Widdecombe in canvas rompers.
What the original Avengers achieved from the outset was a joyous fusion of concept, script, direction and style, in front of and behind the camera. Up to the Sixties, heroines wore starched petticoats, had fluffy hairstyles and their pert mouths were wide open in a permanent red O of surprise.
In The Avengers, Steed's first partner, Cathy Gale (Honor Blackman), kicked open the door for a new style of heroine. And it was Emma Peel who danced through it with a foxy-feline power that has not waned by a single watt in three decades.
Diana Rigg is back on our screens soon, hooray. Not just as Emma Peel (Granada Plus are rerunning The Avengers from 1 September) but in a new role that of Twenties detective Mrs Adela Bradley. Not, I fancy, a name that is anything like as familiar as other TV detectives such as Miss Marple.
Adela Bradley is the creation of Gladys Mitchell, featuring in 41 of her novels. For the benefit of those unacquainted with her work, Ms Mitchell combined writing with teaching. She taught English, history and games at girls' schools for 40 years until she retired in 1961. Her first book was published in 1929 (when she was 28) and her last in 1979. She died in 1983.
To describe her heroine as an unconventional divorcee is to say that Attila the Hun was into pony-trekking. The Roaring Twenties might have brought about a slight slackening of the old social corsetry for girls but for most this meant no more than airing their knees in flapper skirts. Adela Bradley insists on airing both her intellect and her opinions. Here is Mrs Bradley on marriage: "One of those things that is best to get over and done with early in life, like chickenpox." On the countryside: "A soggy sort of place where animals and birds wander about uncooked."
It is astonishing that a TV audience which dotes on detectives, male and female, has not already been introduced to this woman.
But the BBC is making amends with the first of a series of Mrs Bradley murder mysteries. She will be a smasherooney hit. If the nation does not instantly clasp Adela Bradley to its bosom with a collective squeal of delight, I will eat the leather gaiters worn by her trusty chauffeur, George Moody.
The Mrs Bradley Mysteries have a lot going for them as TV material.
There is, at their core, all the arch opulence of Twenties modes and manners. Here is Mrs Bradley questioning a semi-paralysed girl in a wheelchair about her marriage plans, abruptly halted by her fiance's unfortunate mishap in a country-house bathroom.
"Did the question of physical love never arise?"
"Of course not."
Those were the days. And along with the appealing Twenties innocence go the costumes. Women's fashion hit a peak that has never been attained since.
Or so it seems, as Diana Rigg sways into view. No leather catsuit, one needs hardly say. In those days leather was used to make boots for chauffeurs.
Women were swathed in swishy, floaty fabrics that clung only where and when it mattered. No wonder the national vocabulary suddenly began to glisten with words like "it" and "oomph".
It would be ungallant to mention Ms Rigg's proximity to the Big Six-Oh and unnecessary, too. Swathe her in plastic garden mesh instead of satin and velour and she will still be Queen of Cool.
Not just because she looks good but because of her ability to project female strength. Patrick Mac-nee once reflected that in The Avengers Steed was the woman and Emma Peel was the man. An interesting thought. One that might disturb the dreams of impressionable chaps.
It is, however, an observation sparked more by the contrast between the Avengers girls and the TV heroines who preceded them than what we now call role-reversal.
The return to our screens of Diana Rigg is an immediate prompt to scan the horizon for comparable icons. They are not easy to find. American TV goes out of its way to put candidates forward but steam issues from the ears of British women whenever the name of Ally McBeal is touted as a modern role model. Next week Lea Thompson and Brooke Shields can be seen on Channel 4 as the stars of two more single-women sitcoms (Thompson in Caroline in the City, Shields in Suddenly Susan) but a straw poll suggests that the only American characters with whom Brit girls identify are Roz (Peri Gilpin) in Frasier and Rebecca (Kirstie Alley) in Cheers, with an honourable mention for Amanda Donohoe in any role.
And what of British heroines?
Pauline Quirke as Maisie Raine, Elaine C Smith in Rab C Nesbitt, Kathy Burke as Waynetta Slob and Daniela Nardini as Big Anna in This Life. With the striking exception of Ms Nardini, this is a list rather stronger on character than on oomph.
Diana Rigg reigns on, unchallenged and unchallengeable.
The Mrs Bradley Mysteries, BBC1, 31 August; The Avengers, Granada Plus, daily from 1 September.