Grantchester (ITV) is a mild little detective drama which is fine if you like that sort of thing.

This programme has surely been kept from its natural slot of cosy Sunday evenings by the juggernaut of Downton Abbey. Having been displaced to Monday night, where it feels rather small and lost, it tried to prove its credentials by including sex. There were two sex scenes in all, but they were too short to be of any real satisfaction, which I believe is a common complaint. They were also too short to dispel the notion that this drama belongs anywhere but placid Sunday nights.

It was set in rural England in the 50s and the main character was a handsome young vicar, Sidney Chambers. There were lots of scenes of him cycling through the village whilst dogs bark and shopkeepers wave. All was bucolic and easy and misted with nostalgia but then the bleak topic of suicide elbowed its way in.

Sidney was the only vicar willing to conduct a funeral service for Stephen, a local lawyer who had shot himself in the head.

The mourners were suitably glum, except for one: a femme fatale type called Pamela, gleaming with red lipstick, who slinked up to Sidney at the wake and whispered that this was no suicide - 'I mean murder, Mr Chambers!' She and Stephen, a married man, had been planning to run away to the French Riviera. 'We were going to live as we had never lived,' she said. 'To dance on warm summer evenings under the stars.' What ridiculous dialogue!

Then things got even more ridiculous. Based on no evidence at all, merely this woman's tearful belief, Sidney started investigating the case. He was not a detective and had no evidence, no motive and no reason to believe a case even existed, and he most certainly had no business being in the police station sifting through the files and crime scene photos - yet there he was. You just had to accept that for the plot to advance. You also had to accept that the case was nudged along by paltry revelations like, 'the whisky in the decanter was of a cheaper variety!'

There may have been murder, suicide, sex and a femme fatale, which all seemed promising for a rural detective drama, but any sparks in the story were forever being dimmed by the plot's clunks and wobbles. It plunged even further into the implausible as Sidney enjoyed a picnic with his girlfriend, Amanda. All was rosy and sweet as she clung to his arm, but then she suddenly whipped off a glove to reveal a diamond ring from someone else, declaring, 'I've finally got my man.' So they're not a couple? But they were? But not now? As with the other floppy illogical bits, you just had to accept this.

Pondering the ending of his relationship, Sidney had a brainwave. Stephen's suicide note had said things like 'it can't go on' and 'it has to end'. Seen in the new light of a broken heart, could this have been a letter to a lover, ending a relationship, rather than a suicide note? We knew Stephen was married and we knew he was having an affair with Pamela, but did he have any other birds on the go? What about his weepy secretary? If he was writing to break things off, which of these was the woman scorned?

By now you could work it out by process of elimination: it won't be the wife as that's too boring and it won't be the femme fatale as that's too obvious, so that left the frumpy little secretary who apparently just couldn't allow Stephen to go off dancing under the stars with Pamela. You could pinpoint the killer by deciding which woman was the least sexy, and so the least obvious candidate for a crime passionel. There was no room for nuance here: just pick the one in the cardigan who doesn't wear lipstick.

And it was then that Grantchester, having found itself out of its comfort zone, far from rickety bicycles and village greens and lanes dappled in sunlight, made a clutch at the twee and brought a puppy into the story, and it all ended on a cute canine note.

Grantchester was so steeped in cliches that I thought it might be a parody but it's based on a series of novels. It seems you're meant to take it seriously but, just as you refuse and turn away in boredom, a puppy is brought out and wets the carpet and the housekeeper chases it, exclaiming, 'what the Dickens!' So Grantchester is mildly comic too, meaning you can't hate it. You can't despise a programme so soft. They might as well push the puppy in your face and make cooing noises, saying, 'oh, you can't hate us. Look at this iddle widdle doggy….'