Malcolm Webster, played superbly by Reece Shearsmith is frighteningly credible. He has an effective way of worming his way into the affections of women, but has several character failings. He is none too good at managing his money, has a tendency to various sorts of dishonesty, and, worst of all, seems to regard his partners as wholly dispensable once they latch onto any of the first two.
The police have extremely strong suspicions about Webster, particularly latterly after his first two marriages, but are constricted by protocol from taking action, much to their frustration. This is a chillingly realistic portrayal and one can only cringe as one lie after another trips off Webster's tongue. Whilst he is obviously very happy with his girlfriends and wives initially, it is clear to the viewer when his attitude towards them changes, much more so than to his partners themselves.
If you missed this on TV, I would certainly recommend you get the DVD. The acting is excellent and mention should also be made of Webster's three partners, Claire (Sheridan Smith), Felicity (Kate Fleetwood), and Simone (Archie Panjabi). The final shocker for me was realising at the closing credits that this was a true story!