Truelove is the rare show that can combine elements of a thriller with real emotional propulsion. The fact that it addresses so many issues about aging, illness and death in a way that’s more matter-of-fact than maudlin is an achievement.

This drama took a while and a lot of exposition to warm up, a group of old friends, all over 70, who now only meet up at funerals, making a pact while drunk at a wake that they won’t let each other suffer like poor old dead Dennis had done, wretchedly, from cancer. But once it had set out its stall it was compelling, and pretty brutal stuff.

Truelove is rather glorious in parts, despite the subject matter. For starters, it soon develops the structure of a thriller. .... It also does that all-too-rare thing of depicting older people as interesting and complicated and still up for having a damn good time.

Full of great lines, but also deft, dense and, as we move through the episodes, deeply moving.

Some of the needle drops here are perfect and lovely, while others are so on-the-nose they make your teeth ring. Understated, textured arguments exist alongside flat, dumb ones. The show becomes shallower but more propulsive as it goes.

A couple of episodes in, developments become somewhat unrealistic, and it’s unclear how deeply Truelove intends to delve into the sensitive, multifaceted dilemmas of assisted dying. Still, the concept is intriguing – a pithy thriller about euthanasia – and the small screen is lit up with grey power.

The tonal shift between the first episode’s opening act and its closing one will leave some viewers with whiplash. .... Still, with its excellent cast and unusual, if scattershot, tone, Truelove has a lot more to say than most of the limited-series dramas we were served over Christmas.