to be critical of the police...

In a democracy we are allowed to be critical.

Haven't heard about this - were the police aware he had covered himself in the liquid?

www.guardian.co.uk/uk/2013/apr/26/man-dies-police-taser

It seems they had been warned that he had inflammable liquid with him.
There have been several deaths and injuries from tasers but I think there is still some proposal to issue many more police officers with them.

The person who called 999 told the police that he had a can of 'flammable liquid'.

That's absolutely terrible - what a horrible way to die. It seems the police need better training. It must have been a horrific experience for them too and I would imagine will be difficult for them to put it out of their minds.

The figures for the use of tasers are increasing all the time and, though they are only supposed to be used in exceptional circumstances, this doesn't appear to be the case.

This is by no means the first instance of inappropriate use of tasers by the police. Wasn't there an instance not all that long ago where a man in the throes of an epileptic fit was tasered two or three times? And what about the chap carrying a Samurai white stick because he was blind?

The police, especially the Met, have been allowed too much autonomy and power. Many of them see themselves as above or outside the law.

Before taser firing the police give lots of warnings - but just maybe training hasn't covered taser v. inflammable liquid! And has it been proved that the taser did cause the inflammable liquid that the person had already doused themselves with to fire up, or just maybe the person lit it themselves, as they may have intended to do in the first place.

Of course YANBU - the police in the Uk have improved beyond all recognition in the last 40 years but it would be nothing short of a miracle if they were ever perfect. And we pay their salaries.