Life begins at 60 for Harriet – as she proves a point to all the young guns

It is wrong to judge anyone solely on their age, but somehow you don't expect such a high-profile politician to be that old, especially when the new leader of the Labour Party looks as if he should be organising a march in the students' union.

Indeed, the fact that Ms Harman is still going strong impresses me more than any of the ideas she came up with in government.

She says that life begins at 60, and perhaps she will be remembered more for this assertion than anything else. It certainly gives those of us approaching middle age something to think about.

As Ed Miliband took the stage at the Labour conference, I looked at my husband and asked: "Would you trust this man with his finger on the nuclear button?"

And he agreed that, despite his long apprenticeship in politics, at 40, he simply didn't look as if he had life experience equal to all that responsibility. Time will tell.

But I'm only 42 – the same generation as the Milibands, Ed Balls, Andy Burnham, David Cameron and Nick Clegg – and even I am suspicious of this

trend for younger and younger political leaders.

We've seen it all before with Tony Blair, just 43 when he came to power. After that dream turned so sour, you can't blame us for being so cynical.

And when you have held the most important job in the country so young, where do you go after that? A tour of provincial bookshops promoting your memoirs is hardly the best use of such formidable talents.

Party strategists work on the simple assumption that the way to engage the youngest voters is to promote the youngest leaders. But I've got news for them. Young people under the age of 21 can't, in general, tell the difference between a 42-year-old and a 62-year-old. Everyone looks ancient to them. Even their own 30th birthdays seem like an impossibly far-off milestone.

They don't really care if David Cameron proves his fitness by cycling to work and fathering new babies.

It is us in the middle who actually worry about it; are these people, who we went to university with, who went to Billy Bragg concerts and built shrines to Morrissey in their bedrooms, capable of being our leaders?

I reckon it is a bit of our denial on our part, too. We can't believe ourselves that we have grown up enough to be considered capable of such authority. Surely it can't be 25 years since we were all freshers, staying up all night to tie ourselves into ideological knots over Greenham Common?

When I look at these 40-something politicians, I still

find it hard to separate them from the protest banners of our shared youth.

When I look at Ken Clarke or Tony Benn, I think, "They've been around the block a bit". Whether I agree with them

or not, I respect their judgment, born out of the wisdom of their years.

I'm not saying that we should do as they do in North Korea, and prop up our political leaders until they drop of exhaustion, but as Ms Harman, and other senior politicians, such as Vince Cable prove, 60 may well be the new 50, or even the new 40.

Young bloods have the energy, sure, and the life of a modern politician must be extremely demanding physically, but what do they actually bring to the party? And is it right to pension off older politicians to the Lords or elsewhere when they are deemed to have passed their

sell-by date?

This is a particularly timely debate. The idea of a fixed retirement age, with us for almost a century now, is looking distinctly 20th century. A recent survey says that 70 per cent of us expect to work forever.

Talking to my first-years at university this week, I warned them that it is best to choose a career they actually like because it is likely that they will be working for a very long time.

They see individuals, such

as Sir Alan Sugar, still running

his companies at 63, and

then they see politicians disappearing from view as

soon as they get ready to claim their bus pass.

And it is no wonder that they become so disillusioned with those in power telling the country that they must do one thing, and then doing precisely the opposite themselves.

As the Prime Minister keeps on telling us, we are all in this together. If we are to approach the whole big thorny issue of retirement honestly, we can't have one rule for one lot, one rule for the other, and a mess of regulations and rules in the middle which discriminate against those who are happy

to carry on working into their sixties and seventies, but do little to protect those who feel that they can't.

And if we see older politicians being led gently – or, in some cases, booted off – into the sidelines, it doesn't give the rest of us much hope.