There was something noticeably absent from BBC1's documentary about the making of Lucas & Walliams' Come Fly With Me: laughter.

We didn't laugh when we watched the series, either. It wasn't very funny. But we thought the people who made it might've felt differently. They certainly stressed the importance of being funny, as they spoke to interviewer Mark Lawson (seemingly employed to give their work an air of gravitas).

"You have to be really sure it's funny otherwise it will be awful," explains Walliams. But Come Fly With Me wasn't funny. Well, the children recreating the sketches on YouTube clearly found it funny. But children are idiots. Children will laugh at clowns, and clowns are shit.

Throughout the plethora of behind-the-scenes clips, the Come Fly With Me set remains a laughter free zone. Matt & David take themselves and what they do very seriously, which would be fine if what they were doing was worth taking seriously. But it isn't. They dress in ridiculous costumes and make the same tired, repetitive jokes in comedy foreign accents, for a living. It worked for Officer Crabtree in 'Allo 'Allo!, but it doesn't work here.

Filming the show at Stansted airport only adds to the misery, as feckless members of the public distract David from a vital comedy monologue 'till he's at breaking point. It felt mere seconds away from an Elton John-style meltdown. But it's Matt who storms out of a sketch, frustrated by the belief he's not nailing his performance. But it was the material he should've been upset about. Lucas is still a sublime performer, but he's letting down his own talent with this crap.

As Walliams acutely observes, "The problem with doing comedy is if it's not funny it has no value". He seems to lack the self awareness to realise the irony. Or perhaps they both realise it, which is why the entire production feels so joyless.

We learn it was the Beeb who chose the airport themed sketch/sitcom. And it feels very much as if Matt & David then found themselves stuck with an idea neither of them felt any passion for. They seem to have lost the playful glee that made the first series of Little Britain so refreshingly funny, and gone are the wild imaginations that gave Rock Profiles its flashes of brilliance. And now they sit with serious expressions, wearing black, on a black sofa in a black room, offering no greater insight than the fact they do the voices when they're writing and that they were worried they were unable to depict straight male characters. At one point Lawson looked as if he'd nodded off.

Asked if they had any qualms about blacking or browning up, Walliams replied that it might be a problem if they played Japanese schoolgirls for the entire show but, "For a couple of minutes it's acceptable". Acceptable to whom?

At the start of the documentary, Matt Lucas asks the question, "Can we do something better than Little Britain?"

Computer says no.