Dalziel And Pascoe (BBC1)

ZOO owner Guy Latimer is all for keeping things neat and tidy. "I really just want him scraped up and out," he declares. This is understandable. It's not good for business to have bloody body parts scattered about the tigers' cage. A leg here, a head there, something unidentifiable everywhere.

Latimer, as played by Christopher Cazenove, snarls as much as his tigers once Det Supt Andy Dalziel is on the case and rattles his cage. Hence his impatience with clearing up the body remains.

The pair have history, as they say in this type of detective series. Latimer was involved in a murder case 25 years previously in which all the loose ends haven't been tied up yet.

This latest mysterious death - we must assume that the dead man didn't volunteer to be eaten - throws up all manner of horrors, not least the sight and sound of Warren Clarke's Dalziel singing Do You Think I'm Sexy?.

The two-parter has everything you want from a TV thriller - a pair of familiar detectives leading the investigation, a good quota of guest stars behaving oddly and a plot so complicated you daren't nip out to make a cup of tea in case you miss a vital clue.

This story was padded out with a tiresome personal sub-plot in which Pascoe dithered about giving up his job and going to America to be near his daughter.

More people die - drowning and drug overdose - in tonight's concluding part before Dalziel cracks the case. Whodunit? That would be telling. I'll just say that whatever's being kept in the freezer in the storeroom is a big clue.

The Stepfather, this week's ITV1 thriller, also finishes tonight in a finale that will test both your credulity and patience. It all begins so well, something just a bit different to the usual dramas occupying this slot.

Philip Glenister is Dougie, whose wife died and his teenage daughter went missing three years ago. He gave up his job as a teacher to became a mini-cab driver so he could cruise the streets looking for her. Now he's marrying Maggie, a divorcee with a 15-year-old daughter Scarlett, who's a bit of a handful. She thinks Dougie is a creep and makes life hell for him.

So far so normal, or as normal as it gets in a TV thriller. Then Scarlett goes missing. Dougie is the obvious suspect, but gradually Maggie's ex, barrister Christopher, is dragged into the investigation. He makes videos of his daughter "singing like some little Lolita" and likes his women to dress up as schoolgirls.

Sounds like all the makings of a steamy Tennessee Williams drama, let alone an ITV1 two-parter. The interplay and shifting relationships between the main trio of Glenister, Robert Bathurst and Lindsey Coulson made the opening part very watchable.

Things go pear-shaped tonight as the investigation gathers pace. The police, led by the same detective who searched for Dougie's daughter, are useless so it's left to the parents to solve the mystery.

We are led into the world of hardcore porn websites, sex abuse, incest, secret mistresses and schoolgirl pregnancies. The human drama gives way to just another sleazy thriller, but it's still better than most.