Seventy is the age at which "old" starts

On my way to take part in a public conversation with Shami Chakrabarti, director of Liberty, I cross the serene courtyard of the British Library in north London. Its broad, cool spaces induce just the mood of calm contemplation that books demand. I enter the hallowed portals and, handing over my bag for inspection, I hear all hell break loose. At the top of the stairs, a live band is giving full vent to ear-splitting sounds, destroying the peace in this, the very epitome of Britain's library culture. What is going on? Is this a foretaste of what Andy Burnham apparently wants to bring to all our libraries, minus the mobile phones and fast food? I cringe my way to the information desk. I am told that the music is part of a programme called Late at the Library: "a scheme to attract young visitors". But if they'll only come for the band, and they can hear bands everywhere else in London, why fill the British Library with yet more noise?

Mumbling like a grumpy old woman, I head to the lecture rooms where I meet Shami. My complaints are met with stern rebuke: "Oh, no, no . . ." she says. "It's after library hours . . . they're a good group. They're called the Levellers." This stops me in my tracks. The original Levellers were of course a political movement on the outer wing of Oliver Cromwell's New Model Army. The library is mounting an exhibition called "Taking Liberties", which traces Britain's struggle to establish its hard-won freedoms. Are the musical offerings some sort of wry complement to the visual ones, I wonder? Okay, then, I retract my objections.

The exhibition itself is brilliant. People are queuing to see the Magna Carta, the Declaration of Arbroath, the 1832 Reform Act, and myriad pages of paper and ink that have made us who we are and able to sleep soundly in our beds without fear of arbitrary imprisonment without trial. Or so I think. Shami soon puts me right, giving a fine exposition of how - in the name of the war on terror - the state is seizing more and more dangerous powers and how only eternal vigilance will keep us free. The exhibition does more than inform us; it is a reminder to keep up the noble tradition.

The young soldiers, war-weary and exhausted, clambered down from their bus and into the arms of their families, still wearing the uniforms that had so recently camouflaged them in Helmand's deserts. And there were of course some who didn't come back. Seeing the troops return always brings a lump to my throat, and never more so than now, when our army out in Afghanistan is going through hell. Wherever you stand on the war itself, this week there has been a real surge of admiration and affection for our troops. But there is another way we could show our esteem and that is through art, which can express how we feel, too.

A couple of years ago Turner Prize winner Steve McQueen worked with 137 families who had lost relatives to the war in Iraq, creating a work called "Queen and Country". It is made up of facsimile postage sheets, each stamp a portrait of a soldier who lost his life. It is beautiful and touching, and means a great deal to all those who helped create it. The Art Fund is now calling on Royal Mail to issue an official collection of the stamps, and nearly 14,000 people have signed their petition already. It seems to me that we can never have too many reminders of just what our soldiers are expected to do, how overstretched they are, how many endure repeated tours of duty to the most wretched battlegrounds. Until we get the politics sorted and pull the troops out, we need the constant reminder that this is being paid for by young lives cut short daily, on both sides.

All of a sudden, the phone won't stop ringing. The Government Equalities Office has announced that I am to be the Voice of Older People, and everyone wants to hear my particular gripes about the way the old are treated. Seventy is the age at which "old" starts, by the way. Before that you can call yourself late middle-aged. I have been reeling off matters that irk me about the status of the old. The closing of post offices and public loos, for example. You only notice when you need one. Then there's eating out alone; while newer arrivals are tucking into their grilled sea bass, you are still trying to catch a waiter's eye. On Vanessa Feltz's radio programme, on BBC London, a caller asked what right I had to speak for them. Good question. My answer? Age is a great leveller and the risk of slipping on wet autumn leaves is common to us all. So on I go, taking a deluge of emails and phone calls. In the midst of this, it dawns on me that there are an awful lot of old people, which means our opinions of local authority decisions and government policy really count. So I have high hopes that the government will listen to and hear us. After all, they were the ones who asked me.