WHEN asked how his weekend was, a colleague recently told me he'd "bedded down and watched all eight episodes of True Detective, back-to-back."

It speaks volumes for the way we watch TV today that sitting through an entire drama series in one go doesn't seem particularly eccentric.

The rise of the box set marks a significant change in TV viewing habits. Watching episode after episode of a series, rather than waiting a week for the next one to be broadcast, has turned the watercooler concept on its head. Dissecting last night's telly with colleagues has morphed into comparing box sets.

A couple I know worked their way through all five seasons of Breaking Bad around childcare and other leisure time demands. When I asked why they didn't watch it all when it was on telly, they looked at me like I was daft. "It's too much of a commitment to watch something every week," said one.

They have a point. I often fall behind with a series; recording episodes then never getting around to watching them. I still haven't seen the final instalment of The Missing, and since I now know the outcome I probably never will.

While I too will no doubt succumb to box sets, especially now my colleague has lent me True Detective, the problem I have is that block viewing seems a bit greedy. Everything has to be instant and on tap, we just can't wait anymore.

It has also changed the way TV drama is made. Shows like The Missing and The Fall are achingly self-aware and aimed directly at the box set market - largely students or couples cracking open the Merlot when the kids are in bed.

With mainstream success also comes the inevitable second series - and a bigger, glossier box set. And Broadchurch is a prime example of how this can go horribly wrong.

I found the first series gripping but overrated, and guessed the killer from about the third episode. I wasn't convinced they could squeeze a decent follow-up out of it, and three episodes in it seems they can't. The plot is full of holes, not least the ludicrous trial and amateur witness protection, the dialogue is clunky, and don't get me started on the Broadchurch Gazette, or whatever the local paper is. My main gripe is the style over substance; haunted expressions, sweeping coastal vistas, deafening music - and a big suspension of disbelief for everything else.

The producers clearly had in mind their main viewing demographic - middle-aged women - when they rolled out the female high-fliers of Series 2, but it's not enough. Unless it improves, Broadchurch is destined for the box set bargain bin, jostling for space with other TV turkeys.