Janet Street-Porter: I'm innocent. So the police have no right to keep my DNA on file

I once naively believed in British justice: you were innocent until proven guilty. Sadly, this is no longer the case. I'm just one of the million completely innocent people whose DNA is stored on the national police database – the largest of its kind in the world – and there's nothing I can do about it.

The existence of such a huge amount of personal data, which the police can access without anyone's permission, presumes that we are all potential criminals rather than law-abiding citizens.

Let's try and consider the positives: my DNA may come in handy if a six-foot tall red-haired pensioner with distinctive teeth goes on the rampage in southern England, or if a size 14 female with a broken ankle murders a fellow shopper at the checkout. Otherwise, my statistics will languish un-used in the Home Office until the day I die.

How come? Early in 2007, one of my neighbours complained to the police, alleging that I had shouted a racist remark at her when I found that the entrance to my garage had been obstructed. The resultant kerfuffle cost me thousands in legal fees. I had the paparazzi camped outside my door for days, I featured on the BBC news, and several locals flogged colourful stories to the press about living near me.

After a visit from the police – many weeks after the alleged incident – I went to Islington police station at a pre-arranged time with my solicitor, where I was arrested (but not charged) and spent over five hours doing not very much at all. I made a brief statement giving my version of events and denying the allegations, after which my fingerprints and DNA were taken – something I thoroughly objected to at the time and have done so ever since. I was then allowed to go home, someone having kindly tipped off the photographers who were waiting outside.

Then I waited for months, wondering whether the CPS would proceed with the charges. Eventually they decided nothing was to be done and the whole matter would be forgotten, if it were not for the fact that now the police own my DNA.

Why anyone would need the DNA or fingerprints of someone who has been accused of shouting a nasty word is completely beyond me. I never thought that raising your voice left any DNA or fingerprints, but there we are. If it had happened in Scotland, my DNA would have been erased when the charges were dropped. Not so in the rest of the UK.

The national DNA database was not set up by law and no act of Parliament authorises it. It is a complete scandal that the DNA of the innocent is held in this way, and that the Government always falls back on the "threat of terror" as an excuse. Now a "citizens' inquiry" – a group convened by the Human Genetic Commission – agrees, and recommends that the DNA of anyone who is arrested but not charged be removed from the database, along with that of guilty people who have already served their sentences.

They also want the DNA of children found guilty of minor offences to be removed after a short time, and the panel believes that control of the database should be taken from the Home Office (who claim it is a "key information tool") and administered by an independent body.

The Government's record of keeping highly sensitive information secure is lacklustre. Hardly a week passes without a security breach – files left on trains and computer disks vanishing as regularly as the wrinkles on Madonna's forehead. Of all my possessions, my DNA is the most precious. I want it back.

* No surprise that squillionaires Hans and Eva Rausing were not prosecuted after Eva was found with crack cocaine and heroin at the US embassy. Security risk? Seems not. They paid top lawyers to pursue a "protracted" (their solicitors' words) correspondance with the Crown Prosecution Service, who let them off with a caution, even though police found £2,000-worth of cocaine at their home. Wonder if their DNA was taken?

Dressed to kill Gordon?

Who says that clothes don't tell a story? The minute Harriet Harman is left in charge, she pops on a bold black-and-white jacket to trot along to Downing Street and be photographed making a statement about changes to the law on violence.

Harriet must have been feeling confident; the very same day, The Times claimed that she was the perfect successor to tortured Gordon.

Clothes reveal so much. Sarah Brown's entire body seemed to be rejecting that shapeless pink cardy worn for her photocall in Suffolk. Meanwhile gorgeous Carla vamps it up in a strapless Dior number while clinging to the chimneypots of the Elysée Palace for Vanity Fair. Can't see Harriet stooping to that.

Take the train, feel the strain...

The railways are packed with holidaymakers, but some passengers may find the notion of "letting the train take the strain" hasn't filtered down to the staff. When I asked the bloke in the ticket office why Northallerton station was closed every Sunday evening, and the waiting rooms and toilets locked, he said, "We're having a dispute with management," adding triumphantly, "and we're closing at 3pm this Sunday."

South West Trains (owned by Stagecoach, pre-tax profits last year £174.4m) are also cleverly closing their ticket offices at 84 stations on Sundays or all weekends. My Great Western train from Penzance this week had a buffet open at intermittent intervals, filthy tables, and no water to wash your hands in the toilets.

The staff now use a mangled language which is as unreal as my expectations of decent service. The guard has become a "train host", and when the train is too long for the station she told us "only four coaches will be fully platformed"!