These are woeful times for the disabled in Britain – 20% mandatory cuts in disability living allowance, government plans to coerce disabled people to do unpaid work, a 75% rise in disability hate crime between 2008 and 2009 (the last year we have data for) – and the satire of Ricky Gervais.

Gervais – whose last series, Life's Too Short, told the story of a celebrity dwarf (Warwick Davis) and the various ways he could amusingly fall over – is now back with an eponymous show, Derek, which airs on Channel 4 on Thursday. I watched the pilot yesterday; it is about a care worker and celebrity autograph hunter called Derek. Derek, whom Gervais plays, or rather mugs, with clawed hands, greasy hair and a sort of rolling Frankenstein's monster's gait, is clearly loitering somewhere on the autism spectrum, although Gervais, perhaps not entirely behind his creation this time, says not. "Derek is a fictional character and is defined by his creator. Me," he says. "If I say I don't mean him to be disabled then that's it. A fictional doctor can't come along and prove me wrong."

He is right about the doctor, and possibly wrong about the diagnosis. But where is the evidence of explicit disability in Derek? Gervais has been playing with Derek since the Rubbernecker show in Edinburgh in 2001, but as of yesterday all previous Derek material had disappeared from the internet. We do, however, have the testimony of the comedian Stewart Lee, who watched a clip and "imagined feral children trailing real Dereks around supermarkets, chanting 'Derek, Derek', as they doubtless would were the series to be made, and wondered if, sometimes, discretion is not the better part of valour".

I don't doubt that both Derek and the Gervais character in Life's Too Short, who yawns at Warwick Davis's grandiose fantasies, are fragments of what the real Gervais sees in the mirror, and despises. But comedic writers are often narcissists, fixated on their own capacity for malicious self-obsession; and Gervais can, as he showed in Extras, be very good when his targets are not indefensible.

Gervais claims that in Derek he is satirising prejudice against the disabled. He said the same about Life's Too Short, insisting that we laughed at Davis not because he was a dwarf but because he was "conniving, manipulative, pretentious" – and a dwarf. That the comic set pieces were of this "conniving, manipulative, pretentious" man climbing up bookshelves and falling out of a car, which full-sized people rarely do no matter how manipulative they are, makes me think we were actually laughing at the oldest joke – the dwarf's physical limitations – rather than Gervais's tired defence of a meta discourse that insists we are laughing at the people laughing at the dwarf falling out of a car, which merely gives us permission to laugh at the dwarf falling out of the car. I am losing patience with this argument, which feels more like lazy cruelty than satire. If Gervais were really concerned with the abuse the disabled suffer, there are many things he could do. Instead, he feeds bigots their lines.

But this is Gervais's shtick and it is convincing enough for him to have made a promotional video for a disability job site where, in the guise of a factory manager, he talks about whether he would employ people with disabilities. "Not dwarfs," he says. "They take a lot of time off … Christmas and January panto season. Not the little wheelchair ones – they knock stuff over. Not blind, obviously, a dog's no good to you in here. They can't grip, a Labrador." Is this what passes for disability rights campaigning today? In a culture currently watching the reality show on Channel 4 in which disabled people go on dates, promoted by a sign screaming "Undateable", perhaps it is.

But the real evidence against Gervais's satire is what he says when he is not being satirical, or speaking to journalists. Consider his infamous stand-up routine in 2010, where he talked about Susan Boyle. "Look at Susan Boyle," he says, "if you can. I don't think she'd be where she is today if she didn't look like such a mong." He then inserts a fictional critic: "He said mong! You can't say mong." "You can," Gervais comes back. "It's easy. It's one of the easiest words to say. You just needs lips. Even mongs can say it." Back comes the critic: "Why does he get away with it and no one else can? Ban him from the telly!" Gervais smirks, "good luck", and that bellicose child is, I think, his dominant self. He apologised later; of course he did.

Gervais mentions autograph hunters in his stand-up routine as well. Derek is an autograph hunter and this is Gervais on Derek, speaking to a journalist: "He's better than me. He's better than most people. He's kind, loving, funny, sweet, honest, open-minded, hard-working …" Lovely stuff, but does he mean it?

This is Gervais on autograph hunters in his show: "They are the bane of my life. They're a mess. I don't mean their clothes. I mean their DNA." And so, when Gervais says that Derek is "resilient to everything a harsh, selfish brutal world can throw at him", presumably he is in fact referring to his creator. Ricky Gervais is no satirist. Self-serving hypocrite sounds about right.

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