Last Night's Viewing: The Fish Market: Inside Billingsgate, BBC2Grandma's House, BBC2

Can I commend to you an adjective I'd never encountered before? It's "skulduggerous" and the OED citation would run something like this: "2012 Roger Barton The Fish Market: Inside Billingsgate – 'I've never dealt with such a skulduggerous bunch in all my life and I've dealt with some real villains'."

The meaning I think you can probably work out for yourself, but it may help to know that Roger is one of the more successful traders in the market, and a man who employs the blunt insult as a daily tool of business. He was also the charismatic centre of Jamie Balment's The Fish Market: Inside Billingsgate, a character who finds himself uncomfortably speared by controversial changes in the market where he works.

Billingsgate is still operated to bylaws laid down in 1878, and when Roger was a fish porter's trade union representative he zealously defended the protections of trade enshrined within them. Porters can only operate with a licence, are paid a piece rate on the weight of fish they shift and, one imagines, take a pretty dim view if anyone else so much as picks a sprat off the floor. But Billingsgate's owner, the City of London Corporation, wants to change the rules and Roger, now an employer rather than an employee, is in favour of change. "To them, I'm a Judas," he said. "It's sad and it's painful....[but] the tail is wagging the dog and it cannot go on."

The porters, who fear they will be edged out by cheaper labour, expressed the fierce and sentimental defence of tradition that is always customary with those who benefit from it, whether it's hereditary peers or dock workers. And it couldn't exactly be said that Roger was going out of his way to ease the anxieties of the men who worked for him, refusing to tell them whether they'd still have a job with him under the new rules. But everywhere you looked it was clear that pretty much everything else had moved on since 1878 and that this was a battle the porters are likely to lose. Even Pikey Bill, who is so fond of Billingsgate that he now works as a cart minder, guarding fish boxes for tips and cups of tea, conceded that "It's gotta change."

It's obligatory for all market traders to complain that business is bad and fings ain't what they used to be, but in the case of Billingsgate it seems to be true. Supermarkets go straight to the coast to buy their fish and quotas have an effect too. Not everybody is very happy about modish attempts to change our consumption habits, either. A trader called Mark Morris, who is clearly lining himself up to step into Roger's shoes as Character-in-Chief, was fiercely dismissive of the newly modish pollock: "If the cod's a human being... it goes to the gym every day, yeah? It eats all the right foods. It probably drives a Porsche, right? This... pollock... is sitting at home on the settee in a tracksuit watching Jeremy Kyle and eating a burger." Nothing downmarket about Balment's film, though, which was fresh enough to be still twitching. And it had a seal. In West India Dock.

The current series of Grandma's House ended last night. At least I hope "current series" is accurate because Dan Swimer and Simon Amstell's comedy keeps getting better, its account of repressed feeling and family in-fighting beautifully discordant (the signature tune is perfect). Last night tuned the self-knowledge to an even higher pitch: "That would have been very funny if you'd laughed," Amstell told his mother, after accusing her of compensating for her own disappointing life by obsessing over his career. "Your silence made it seem a bit mean." And then it ended with him glumly watching an old Never Mind the Buzzcocks performance on YouTube, his dreams of love and happiness having evaporated. Hard to believe one laughs at all, really, but I did. A lot.