Most remakes aren't worth the time+money
And it is extremely extremely extremely difficult to see how you can improve on this one, which was a classic back then, and is still a classic now, for the reasons already mentioned...
When the DVD is £12, who needs a torrent? I bought the DVD a year or two back and watched the whole lot in one edge-of-the-seat session.
Troy Kennedy Martin, Bob Peck, Jo Don Baker and a few others no longer with us won't be enjoying their share of the £12, but...
In fact, why isn't this classic BBC production available online to licencepayers in the BBC Creative Archive, announced back in 2003?  In fact where is the BBC Creative Archive, full stop?
This was classic classic classic TV. A repeat would be especially timely as the UK appears to be about to begin the dangerous journey into a new nuclear era. Should be compulsory viewing, for so many different reasons.
Thumbs up for the original, not the remake.