From the window of my flat in London I can watch the Thames as the tides and seasons change. March is a kind of turning point. The river now is full of surprises, forever distracting me from my work. As the skies keep changing, so does the water's apparent colour: blue-grey to brown, to greeny-grey flecked with white, to almost black. The spring tides rush in and out and violent eddies trouble the surface that, agitated by who knows what beneath, can almost seem to boil. And sometimes the March wind, pushing against the flow of the tide, whips the waves into strange, sharp, almost stationary peaks - the current running one way, the wind the other.

When weather, wind and currents are on the turn, say yachtsmen, a curious, choppy and deceptive water (they call it “an uncertain sea”) can be the result. Such a sight is troublesome not only to the sailor's calculations, but to his spirit.

I think we in Britain are on such a sea in March 2008. The economic wind seems to be gusting one way, while the optimistic language of politicians gusts another. Most of my countrymen, in the backs of their minds, harbour doubts and worries about the future; yet few are sure enough to let it spoil their Bank Holiday plans.

TV monitor in hand, I can flick from a worried-looking banker talking about turbulence in the world's stock markets, the possibility of another bank failure and the drying up of credit, to David Cameron at his party's spring conference, cooing about ways of letting parents take six months' paid paternity or maternity leave after the birth of a child, with their jobs guaranteed on return. Or I can follow the argument of a woman indignant that a potential employer did not give her a job on the ground (she suspects) that he had realised she was pregnant. The injustice of it!

My eye can move from a Times column by Anatole Kaletsky, full of hope that all will be well with the world economy, to pages dripping with something close to apocalyptic language. I can walk into a poncified gastro-pub near Canary Wharf on a Tuesday night to find no table available until 10, and a room packed with smart, coolly dressed under-40s businesspeople paying £23 for a small piece of steak, with the offer of a bottle of wine for £200, chalked on to a faux homespun blackboard... but note that the waiters and waitresses are young people from Paris who cannot find work in France. And I walk home past a giant, moving electronic display of world stock market prices, with arrows pointing down.

The newspapers have been full of Budget news and reaction, into which words and phrases such as “robust”, “withstand”, “bubble” and “well placed to weather the storm” recur. I see pictures of the Chancellor, Alistair Darling, with the sweet, shallow eyes of one of my llamas, strangely uncomprehending, registering not even fear, as he stands blank, passive and passionless at the dispatch box and drones from a script about a return to previous levels of growth in just a year or so - all being well - and how the “economic fundamentals” are sound.

Meanwhile, the politics pages and TV discussions are full of babble about the key role in the community played by post offices; or Easter holiday congestion on Britain's roads; or whether it's fair that your concessionary bus pass should depend on your postal code; and whether the nationwide scheme for free bus travel for pensioners will be properly funded; and whether doctors will or won't grudgingly work some extra hours at weekends or in the evenings.

In the Commons Nick Clegg, the Liberal Democrat leader, asks why Gurkhas who retired before 1997 cannot get permission to stay in Britain, and it seems like a big issue; and Mr Cameron asks about whether the Prime Minister will meet the Dalai Lama, and roars of support greet Gordon Brown's reply because MPs understand it. Exchanges on the credit squeeze and world economy draw only confused mutters.

And there's no great debate about the world's or Britain's economic prospects because what is there to say except “fingers crossed”? Over the Thames the metallic clutter of huge cranes above the Isle of Dogs stays rigidly in place, steel arms swinging slowly across the sky, building new skyscrapers: offices and homes for office workers; and they are extending all the platforms on the Docklands Light Railway so the trains can take an extra car because the growing pressure of commuter numbers threatens to overwhelm the service.

Over the weekend I watched again that Peter Sellers classic, Being There. Simple-minded Chance, who has never left his employer's house, watches television obsessively. There are sets in every room, and with short attention span he flicks mindlessly, trivially, from programme to programme, from drama to humour to tragedy to an advertising break. These images are his world. One day he has to leave. Walking for the first time the mean streets of a Washington slum, he is baited by a gang of proto-hoodies. He stares at them point blank, flicking his TV monitor desperately. But they don't go away and he doesn't understand why.

Watching Mr Darling deliver an impotent Budget, his Prime Minister sitting leadenly beside him, you could easily imagine both men flicking urgently at their TV monitors, wondering why the picture wouldn't change according to their preferences. It always did before.

Who knows what's happening? Perhaps nothing, after all. Perhaps this will all blow over. But what unsettles me goes deeper than a sense of mystery about the future. At most junctures in history there arises the feeling of a lull before a possible storm. Heck, we were in a worse state in 1945, or 1979. Danger was more imminent in the Cuban missile crisis in 1962. The fall of the Berlin Wall in 1989 posited bigger unknowns for the future. But at these crossroads the air was full of ideas: strong ideas, competing ideas, confident philosophies, angry dissent. People had policies. Ideologies clashed. Politicians and thinkers jostled to present their plans. Leaders led.

But what distinguishes this hiatus in 2008 from those earlier forks in the road is the impassivity of our politics, and the idleness of political debate, as we wait. There is a sense of vacuum.

There was not in 1979, as there is now, this curious hollowness in the air. Where today is the bold advocacy, the impatience to persuade, the urgency of argument? Where are the shouts of “Here's how!”? It is as though the stage were set for some kind of theatrical climax, but peopled only with stage hands and the rattle and murmur of the scene-shift. Where are the leading actors, the big voices, the great thoughts?

Pictures of David Cameron in his kitchen, a family scene sweetly contrived to frame his thoughts on paternity leave, or whatever, and images of the passionless figure cut by Alistair Darling at the dispatch box, his grey stare charged with all the philosophical depth of a shop-window mannequin, stick in my mind. Are these the spirits of the political age?

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