Quite apart from the fact that it’s got the wonderful David Threlfall in, the current series of Shameless is back to its old standard, and that has already given us some of the funniest, most outrageous, and occasionally most moving TV moments of the year so far – and the series is only barely halfway through!

When Shameless first arrived on our screens it was undoubtedly one of the best new dramas to appear in a long, long time. Perfectly named, it showed us life in the grim underbelly of society and let us know that, although it was hard, gritty and at times dangerous, it could also be funny, exciting, and full of warmth and compassion. Series 1 was brilliant, and series 2 carried on in a similar vein. Series 3 started to lose its way a little bit and fans worried that the writers were beginning to run out of steam, and by series 4 the rot had really set in and it was, most people agree, a bit pants. But with a totally rebuilt set and some cracking new ideas, Shameless came roaring back to form with the current series, which has just been getting better and better.

Interviewed on Channel 4′s Shameless microsite, David Threlfall reveals the secret behind Frank Gallagher. It’s no surprise that his appeal is that he’s not horrible all the time. Behind the man with “intake issues” is a human being struggling to do his best for his kids, and all the time recognising his best often doesn’t even come up to most people’s worst. This pathos is the heart of Frank’s character and also the heart of his humour. If Frank was uniformly nasty, no-one would care if he fell over in a drunken stupor.

This same light touch is now being applied – a little late in the day some would say – to the Maguire family. When they first appeared they were painted as two-dimensional thugs. All bite, a little bit of bark, and absolutely no soul.

In Series 5, we started to get a glimpse of how life really is for the Maguire’s. While they have to keep up the appearance of being hard so as not to be trodden on by other gangs and “families,” in reality they have a stack of issues. Mimi’s body image problems and worries that Paddy has gone off her, Mickey’s homosexuality that he daren’t admit to his Dad, coupled with his pathological inability to get anything right. These added dimensions give the Maguires much greater comic potential as well as many more ways for them to undergo dramatic conflict and resolution.

Last week’s episode, when Frank fell for a stranger on a bus and enjoyed a brief, electric and deeply meaningful fling with her for a few blissful days, was both a dramatic and a comedic masterpiece. It would have been good on any level, but as part of Shameless, and happening to Frank with all his familiar foibles, failings and fears, it was simply brilliant. One of the best stories so far.

If Shameless can keep up that standard of writing five series in, then its future for the next few years must be assured and we can look forward to even more comic gems in the rest of this series and beyond. Long may it continue.