It divided opinion when it debuted last April but there's a charming, ingenuous quality to the offbeat humour in this new comedy series from Ricky Gervais. He stars as Derek, a vulnerable adult working in an old people's home, who reckons he's the luckiest man in the world, surrounded by all of his 'favouritest' people, including long-suffering best friend Dougie (Karl Pilkington) and the home's manager, Hannah (Kerry Godliman). The laughs are bittersweet and there's a poignant truth beating at the heart of the story - the council is looking to cut its budget, which means Derek's happy home faces the chop.

Kerry Godliman on working with Ricky Gervais on Derek

"After seeing Derek, another comic said to me 'well, lucky you! That's your ticket out isn't it?'" Kerry Godliman smiles, a little awkwardly, over a cup of tea.

Last year's pilot episode got a mixed reception, so many were surprised when Ricky Gervais's comedy-drama about a retirement home worker with learning difficulties was commissioned for a full series. Yet here it is, starting a run of six episodes. Gervais writes, directs and stars as sweet-natured, animal-obsessed, autograph-hunting Derek Noakes. Gervais's regular sidekick and stooge Karl Pilkington reprises his role as caretaker Dougie, while Kerry Godliman is the standout performer as workaholic manageress Hannah. This opening episode finds Broadhill care home's future under threat from council cuts. Hannah takes inspectors on a guided tour but her efforts to impress are hampered by tadpoles in the bathroom and a naked guest in one of the beds, leaving the ragtag team struggling to prevent the home's closure. There are tender moments and its heart is in the right place, but the end product is misjudged. Much of the acting is awkward, while the script attempts to wring laughs out of bad wigs, sexual innuendo and gratuitous swearing. You can't help feeling it was Gervais's past reputation and celebrity status which got this made, rather than the quality of the show.

Following last year's pilot (a pilot that should have been shot out of the sky with a shoulder-launched rocket), here's an entire series focusing on the "childlike" and "innocent" retirement-home helper, lazily played by Ricky Gervais as a hunched, gabbling gurner with a comedy combover. This week, the staff, including Derek's best friend Hannah (Kerry Godliman - much the best thing in this), confront a stuffy suit, whose swingeing budget cuts are threatening the old people's home. Oh happy day.

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?

Kerry Godliman: Controversy about Derek is annoying

Derek star Kerry Godliman has said criticism of the comedy show is an 'annoying distraction'.

The pilot last year may have been a bit divisive, but Channel 4 obviously liked Ricky Gervais's Derek enough to order a full series of the bittersweet retirement home comedy - we're just wondering if he can keep that face up for six whole episodes. The Office mastermind's latest project kicks off proper with sweet and simple Derek teaming up with co-workers at the home Dougie (Karl Pilkington, basically playing himself) and Hannah (Kerry Godliman) to save it from closure.

Kerry Godliman asks Brett Goldstein about horror stories

A short interview with Brett Goldstein.

Kerry Godliman interview

Kerry Godliman plays Hannah, a care home manager, in a six-part comedy drama. The show, which had a pilot episode last year, has caused some debate because it features comedian Ricky Gervais as Derek, an employee who seems to have learning difficulties. Kerry tells TV Choice more...

Ricky Gervais in Derek, Channel 4 - review

Despite good performances from Kerry Godliman and Karl Pilkington, the first full series of this care home comedy looks like another slushy mess, says Jack Seale.