Tanks proper - specialised Main Battle Tanks, designed to fight their own kind - are finished, as dead as the all-big-gun battleship (another British innovation). Fighting tanks can't survive under hostile skies, and under friendly skies they have no purpose.
But armoured vehicles are still a big deal, as the past several years have shown. Buried mines and roadside shaped charges can blast through just as much armour as a tank cannon's hypervelocity penetrator. Thus, British and allied troops still prefer to ride behind heavy protection if they can. They also like the ability to get about offroad.
But how much mobility, and how much armour? In Afghanistan, there are lots of places where nothing much but a mule can get along. Often enough, troops operating in these places choose to have no armour whatsoever on their vehicles - quad bikes, Wolf Landrovers etc - if they even use ground vehicles at all. By contrast, there are places in Iraq where the choice is all armour and almost zero mobility - there are vehicles in service there which can't really go off road at all.
It might just be that there is no one-size-fits-all-wars solution, even in counterinsurgency fighting.
Then, apart from the real world, there are the demands of the possible future worlds, usually closely related to the needs of certain service communities to carry on existing. If all you had was FRES UVs, operated by ordinary Tom-Dick-&-Harry soldiers, people might question the need for specialist tank units. So in fact there is talk of FRES Scout and FRES Heavy: in order that the present British cavalry, now mounted in antique Recce tracks and Challenger battle tanks, can have a distinct future to look forward to. No matter that robot surveillance-planes would seem to have stolen the Scout's job as conclusively as air support has stolen the Heavy's, we nonetheless plan to have both.
And while one may beg leave to doubt that we really need Scouts and Heavies as such, it is fair to suggest that more serious ground threats can still appear. Portable guided missiles, able to launch from afar to blast through any practical thickness of armour from above or aside, are already common in Western armies. Our soldiers will need an option for dealing with this threat, which will start to become more and more common - the Israelis are already encountering it.
Frankly, this isn't a debate which is going to be solved in a hurry. There almost certainly isn't any one design - or even any vaguely-related series of designs - which could sort the British Army out even for the counterinsurgency wars it will definitely fight in the next decades. Even if there was such a solution, the Army's squabbling subcultures could never agree to adopt it - their separate existences very largely depend on the differences in their present vehicles. The cavalry are no more likely to admit that tanks are outmoded than the navy is to admit that a surface warship is mainly useful for carrying aircraft. (The big-gun battleship mindset is far from dead, in fact.)
One thing's for sure, though. Our armoured-vehicles industry is actually pretty much moribund. Our defence-electronics and subsystems business is sound, but far from comprehensive - and it needs to use overseas bits. As a result, we cannot build the fighting vehicle of tomorrow on our own - certainly not the proper one, able to track incoming guided weapons and frustrate them somehow. We couldn't even build a jazzed-up old style main battle tank on our own; not that it matters. Nobody needs frontally-armoured flat trajectory hypervelocity guns able to shoot sideways going over cabbages at 60mph any more. Nobody should really worry about the loss of that particular set of design skills.
So it's pretty foolish to mourn the lost era when mighty Blighty could make its own tanks, the more so recalling that our best ever for-real combat tank was the Sherman.
The other thing to remember is that the present state of the UK tank industry is a matter of conscious choices made over the past eight years and more by its owner, BAE Systems plc. The money which might have allied BAE Land Systems with Europe to build a real contender (imagine a British/German tank, now) was spent instead in the States. So it hardly becomes BAE Systems to blame the government for the passing of Blighty's (nonexistent) tank superiority. ®