On Channel 4’s opening night in 1982, Ian McKellen starred in Walter, a drama about a man with learning difficulties who tries to make his way in a cruel world filled with suspicion and derision. In Derek (Channel 4, Wed, 10pm), Ricky Gervais stars as a man with learning difficulties who tries to make his way in a cruel world filled with suspicion and derision. And has Karl Pilkington a best friend.

The contrast couldn’t be more stark. Whereas the future knight and Lord of the Rings star simply was Walter, Derek is the Office boy with a greasy haircut, bad knitwear and facial tics. The cynical might view Derek as Gervais making a grovelling apology for ‘Mong-gate’ when he threw a word around on Twitter in late 2011 which attracted the ire of the Daily Mail (obviously), Susan Boyle and MENCAP. Except the writing of Derek was well under way by then ahead of its pilot episode last spring.

Like the overwhelming majority of modern comics, Gervais’ heart is solidly in the right place but the brain has a tendency to force a foot deep into his mouth from time to time. Taking risks and making an inevitable mistake or ten is part of the comedian’s job description. Here, though, Gervais has gone almost entirely in the opposite direction. Soundtracked by Einaudi, Derek is overstuffed with manipulative schmaltz, and so sickly-sweet that it requires you to undergo an emergency filling just by switching it on.

Shunning the pratfalls of the pilot, Derek is now a conscience-driven series in which besuited health executives visit the care home where the eponymous 49-year-old works, callously poking around to see where cuts should be made or whose jobs can be exterminated. Oddjob man Dougie (Pilkington) is one obvious candidate for the chop, while the delicate situation is not helped by the inexplicable presence of a sleazy waster Kev (David Earl). He brings a certain David Brentness to proceedings, replacing tugging on his tie with slugging on an endless stream of Special Brew while attempting to force himself onto any female (whether old, obese or other) unfortunate enough to cross his awful path.

Gervais’ triumphs here are to show that the previously irritating Pilkington is actually half-a-decent actor and to write a beautiful lead role for Kerry Godliman as the stoic care home leader. Where it falls spectacularly down is through some rather lazy button-pushing (especially with the endless photo-montages of aged residents in their youthful pomp) and in Gervais’ massively distracting central performance which hinders rather than helps the series. And will he ever give the mockumentary genre a break?

Just to prove that Gervais is equally as adept at mucking up other people’s shows, he pops up on his comedy chum Louis CK’s sitcom. In Louie (Fox, Tue, 9pm), he plays an irritating and inappropriate doctor who (believe it or not) has an over-the-top cackle-laugh. The show itself is more Curb than Derek, as CK writes and directs a less than flattering version of himself. ‘Louie’ is a fortysomething stand-up comedian and divorced dad of two young girls who frets about his weight, worries that he’ll never be able to go on a date ever again without making a total ass of himself and seems happiest while playing poker and shooting the breeze with his real-life stand-up friends.

Comparisons made between CK and Gervais are understandable. They appeared together in The Invention of Lying, prefer to do their stand-up in unshowbiz jeans and t-shirt and gained their major success relatively late in life (Rolling Stone recently voted Louis CK as the funniest person alive in a top 50 poll in which Gervais reached number 16). Gervais once dubbed CK as the finest stand-up in America, but it’s unclear exactly what he thinks back: though there is footage of a decidedly unimpressed CK trapped in a lift and at the sharp end of some Gervais banter (with accompanying exaggerated howling, of course). Perhaps CK will reflect on the wisdom of inviting his British comedy chum onto his show and conclude that Gervais needs him more than he needs Gervais.

Derek - a first look at the new series