COWERING behind sofas across the country, a new generation of British children is fearfully transfixed by the terrifying enemies of David Tennant’s reincarnated Dr Who, from Daleks to Cybermen.

Yet at the same time, we grown-ups are happily going about our daily business, oblivious to a threat far more insidious than any confronted by the Doctor; one that imperils the very future of the nation. Be afraid: the Brownerons are coming.

The product of a mutant strain of newly consensual politics, the Brownerons have been hatched from an unholy, and unspoken, alliance between Gordon Brown’s version of new Labour and David Cameron’s modernising Conservatives.

As political gene-splicing goes, the results leave Britain facing the most Frankensteinian peril since the creation of the SDP-Liberal Alliance — but one that is potentially far more serious in its consequences.

The Browneron menace is stealthy and surreptitious. On the face of it, the two sub-species of these political clones, Labour and Conservative, try to look as different as possible. They appear to pose a danger only to each other. To the public, they contrive to look as fuzzily friendly as possible, deploying their fearsome “spin” weapons to enhance their appeal and lull the country into a false sense of security.

Meanwhile, the two breeds of Browneron make a pretence of venomously attacking each other in a phoney war. In reality, they disagree over little and are intently focused on their sole objective: power for themselves.

Still, the Brownerons fire off endless salvoes from their arsenal of dumb-dumb bullets: hollow claims that hit home politically but have little real significance. Small points of difference are exaggerated to appear as if they are matters of real substance. A false conflict is waged over the middle ground of politics.

Before long, Britain is left enveloped in a fog of political misrepresentation and meretricious nonsense. Under this cover, the Brownerons can work quietly to undermine any prospect of real reform and progress. Ideas and debate are smothered by woolly thinking, while any challenge from radical ideas that might thwart the Brownerons’ cynical agenda are demonised as the work of a lunatic fringe.

All of this is a caricature of course. Nevertheless, the emergence of a new, if undeclared, brand of consensus politics in Britain appears increasingly to pose a genuine threat to real debate and political progress.

If reform and political innovation emerge from the clash of ideas, then the increasing drift of the two main parties into a stultifying, apathy-inducing consensus is an ominous development for the country’s — and the economy’s — prospects.

Back in the mid-Fifties, even before William Hartnell materialised on our television screens as the first Doctor Who, Britain was in the grip of an earlier outbreak of (declared) consensus politics. The broad ideological agreement between Rab Butler, the Conservative Chancellor of the Exchequer, and Labour's Hugh Gaitskell, led The Economist magazine to coin the term “Butskellism”.

Arguably, this centrist agenda can now be blamed for perpetuating the fundamental flaws in Britain’s economy that were responsible for a postwar decline only halted by the Thatcher revolution in the Eighties. The toll from Butskellism was severe. Much of the Thatcher solution, when the nation was at last forced to confront the consequences, was equally so in the pain and dislocation it caused.

Now, the danger from the Brownerons could prove equally grave.

Neither Brown’s Labour nor Cameron’s Conservatives will accept this depiction, but the reality is that, across swaths of policy, there is remarkably little difference between their present platforms.

The ground between the two sides on economic policy, especially over tax and spend, is the narrowest of all. For all their noisy protestations that a gulf of analysis and intent stretches between their entrenched positions, the no-man’s land in this conflict might be measured in inches.

This is an unhealthy condition for the politicians themselves, and for the country. The public is much to blame. Voters’ persistent belief that it is somehow possible simultaneously to spend more and tax less without excessive borrowing has led politicians to encourage their faith that they can have their cake and eat it. It is the pandering politics of Mr Kipling.

The phenomenon of these new consensus politics has been fuelled, too, by new Labour’s second-term success under Brown and Blair in shifting the terms of political debate decisively in favour of the Chancellor’s strategy of tax and spend.

Despite Labour’s continued substitution of rhetoric for reform in the state sector, the electorate’s patience as it waits for Mr Brown’s billions to bring desperately needed results in public services seems yet to be exhausted.

But that patience may not last forever, and for both Brown and Cameron, there is a real danger that the seemingly comfortable refuge of a populist consensualism will prove to be a nasty trap.

The Chancellor may believe that talking up the cause of reform while failing to take any actions that might court unpopularity — or alienate his legions of public sector supporters who owe their living to the state — will get him through to an election victory as Prime Minister.

So it may. But this strategy could backfire badly if, as seems likely, his spending spree forces him eventually to raise taxes beyond public tolerance and the electorate grows more severely disillusioned with the persistent failings of public services.

For Mr Cameron, the risk is that he fails to offer more radical choices just as the watershed moment arrives when public disillusion with a failed public spending experiment starts to make bigger changes look a lot more appealing.

Finally, for all of us, the vacuum of ideas created by Browneron blather denies us a choice of visions, condemning voters to pick instead only between rival managers of the same policies on the basis of personality and flannel. It is a prospect that makes the back of the sofa look an appealing refuge at the next election.

Times Recommends

• C&G axed - 1,660 jobs to be lost
• UK house prices rise 1.1% as buyers return
• Mixed reaction to US banks repaying bailouts