The 39 Steps? Brilliant. Nothing like a black-and-white Alfred Hitchcock thriller at this time of year, a classic movie the family can still gather around. Unfortunately last night's The 39 Steps really was nothing like that. It was a BBC remake, “based on” John Buchan's rip-roaring spy novel. That's based on as in “stood on and wiped its feet”.

First published in 1915, Buchan's book (proper title, The Thirty-Nine Steps) relates Richard Hannay's frantic quest to prevent a German spy ring stealing Britain's naval defence plans on the eve of the First World War, while avoiding wrongful arrest for murder. It was top-class wartime propaganda about how one man finds himself through sacrifice in his country's cause. By all accounts it went down well with Tommy Atkins in the trenches.

These days, however, the BBC is uncomfortable with militarism and patriotism, while many viewers prefer the “who am I/what am I fighting for?” uncertainties of a postmodern agent such as Jason Bourne. Perhaps the only way to do The Thirty-Nine Steps now would be a fashionably “ironic” send-up, as in the recent award-winning theatre version.

But the BBC was in humourless Auntie mode here. It updated the story by introducing a female character, Victoria (Lydia Leonard), as a catalyst to Hannay's (Rupert Penry-Jones) awakening - what feminists used to call “consciousness-raising”. She proclaimed herself “a suffragette and a spy”, and they had cross-country arguments about women's rights while enemy agents tried to kill them, before he fell in love and thanked her “compassion and commitment” for showing him the way. Then, inevitably, she got shot.

The overall effect was to turn Buchan's blood and thunder tale into a pallid politically correct Enid Blyton story, peopled by characters who I could not easily warm to on a tropical beach never mind wet Scottish moors. Almost all it seemed to have in common with the original were the sort of unlikely plot devices for which Buchan was infamous. Not only was this version less exciting, but also less intelligent than his Boys' Own story. So we knew a German was evil last night because he wore black leather gloves. By contrast, Buchan has Hannay conclude that his enemy was driven by a “white fanatic heat” because “in his foul way he had been a patriot” too. If you want some post-Christmas excitement, read the book - it will feel far shorter and sharper than this adaptation.

It is not every night of the year that one can say ITV produced a cleverly conceived historical drama. But lo, it came to pass. Affinity, based on Sarah Waters' ghostly novel, was not as racy and headline grabbing as Tipping the Velvet, her previous televised tale of lesbian love, but seemed none the worse for that.

Margaret Prior (Anna Madeley), a Victorian bourgeois spinster under pressure to marry, sought purpose by becoming a visitor at grim Millbank women's gaol, where she met the young spiritualist, Selina Dawes (Zoe Tapper), who claimed her crime was committed by a dark spirit, Peter Quick. It became clear that, in Selina's words, “You are like me”: both were lesbians (Margaret's only lover having become “ordinary... boring” and married her brother), and both were in prison - one literally, the other trapped in the conventions of a society that even denied her free access to her own inheritance.

The story was handled sensitively, with no “look, ain't it outrageous, phwoar!” salaciousness, and the spiritualist “black circle” (séance) scenes were almost other-worldly. In the end it turned out that Peter Quick was in fact Selina's real soul-mate, the hard-faced maid Ruth - disguised to enable the pair to prey on wealthy women - who also helped in her escape from prison and rip off the distraught Margaret.

I recall reading that one reason lesbianism was not outlawed at the same time as male homosexuality was because the authorities feared that acknowledging it might put ideas into the heads of serving girls sharing rooms. Affinity ended with the neat revelation that, whereas the sapphism that eminent Victorians denied was very real, the spiritualism in which many of them believed was absolute bunk.

Another struggling woman who ended up in prison on ITV was Gemma the Elvis-obsessed embezzling parking fee collector (Connie Fisher) in Caught in a Trap on Boxing Day. Ms Fisher won a TV contest to play Maria in The Sound of Music, but some doubt whether she has real star quality, or sufficiently starry teeth. Whatever; she was great as the lost girl Gemma, trapped between the office bitch and bitching stepmother (Geraldine James, good as ever). She ended up smiling warmly with those teeth, holding hands across the prison visiting room with the distinctly un-Elvis-like stuttering boy who adored her, the King's Always On My Mind playing on the soundtrack. It was almost touching enough to make me forgive her Julie-Andrews-Murders-Elvis star turn at the office karaoke.

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