Last Night's Viewing: Derek, Channel 4

Ricky Gervais has insisted that Derek, the titular lead of last night's comedy "pilot" is not in his view disabled. Then again, Ricky Gervais thought there was nothing wrong in using the word "mong" to accompany comic gurning on Twitter, so you might not want to rely too heavily on his judgement of fine distinctions in this area. You might reasonably be a little wary about Channel 4's bona fides, too, given the promotional marketing (if not the actuality) of its current series The Undateables. Hardly surprising really that Derek has already stirred up a minor fuss over its propriety. Is this a comic exploitation of a group already subject to far too much callow mockery, or is it, as Gervais would have us believe, an empathetic account of an oddball outsider?

The only way to judge it fairly, I would have thought, given his previous, is to pretend that it's made by somebody else entirely. What kind of review would Derek get if its director and lead actor had never done anything before? And if that was the case, I think you'd have to bring in a mixed verdict. You'd certainly feel uncomfortable about the physical presentation of the character, with his hunched, tottering shuffle and his open-mouthed gawp. And you'd be rightly dismissive about any pre-broadcast claims that this character wasn't supposed to have learning difficulties. Derek is simple, to use an outdated terminology, which means that a comedy about him really can't be. In what way is he laughable, exactly?

Hannah, the care-home assistant who works with him, doesn't specify: "Derek just cracks me up. He's just funny. I think he's hilarious," she says. As if to illustrate her point, Derek then forgetfully sits down in his rhubarb crumble and custard, a Norman Wisdom bit of slapstick that isn't hilarious at all. It isn't any funnier when he falls in the garden pond and runs naked through the recreation room. But elsewhere the depiction of a certain kind of mind, guilelessly eager to share its enthusiasms and prone to misunderstandings at least has the accuracy of good comedy. Whether you feel comfortable laughing, given that, unlike Hannah, you're on the outside looking in, is more questionable. And a bit of plangent piano music on the soundtrack – standard television code for "be a bit thoughtful here" – isn't nearly enough to settle it in Gervais's favour.

On the other hand, this is a comedy that openly – even clumsily – identifies itself with the better angels of our nature. There is explicit contempt and bullying on screen, but it's shown in characters who manifestly should be better: Karl Pilkington plays a sour caretaker, indignantly denying Derek's claims to friendship and there's a scene in which a group of girls in a pub mock Derek for his appearance. One of the latter receives a corrective head-butt from the protective Hannah, while Pilkington's character is shown to have been belatedly shamed into decency by Derek's earnest generosity of spirit. Then the episode ends with a sequence so mawkishly right-minded and sentimental that it calls to mind the "Simple Jack" pastiche from the film Tropic Thunder, a satire on Hollywood's dulled moral instincts. If Gervais is guilty of anything here it's not cynical exploitation, but self-regarding naivety. Getting your character to say "I'm not clever or good looking but I'm kind" won't magic away the hazard. Street bullies simply don't care how sweet-natured their victims are.

It should be possible for comedy – which can be the most humane of forms – to deal with this subject matter. In real life, after all, disabled people aren't surrounded by a fiercely policed "Laughter Forbidden" zone. And some of the discomfort that Derek generates stems from how rarely such a thing has been attempted. If you were feeling very kind indeed, you might want to give Gervais credit for trying. But I don't think you'd conclude that he'd succeeded.