Dom Joly: Chernobyl – where better to slake a tourist's thirst?

Spring is in the air down in the beautiful Cotswolds. Bluebells carpet the woods while lambs are agambolling in the lush fields. Sadly I know this only from telephone calls home as I'm on a weekend break in Chernobyl.

Only 5,000 visitors a year leave Kiev, the handsome capital of the Ukraine, to take a minibus to the "exclusion zone". This is an area 30km around reactor No 4 of the V I Lenin nuclear power station that blew up on 26 April 1986, covering Europe in a radioactive cloud.

I was at school at the time, and I remember newscasters pointing to frightening maps of the Continent showing wind patterns and the advance of "the cloud". Some teachers at school started wearing masks and doom-laden predictions were everywhere in the press.

Sound familiar? Like swine flu, the radioactive fallout from Chernobyl was an invisible enemy that terrified populations by its very non-tangible existence. Around Chernobyl, 140,000 people were moved permanently out of the exclusion zone. Official figures of 2,000 deaths do not reflect the huge scale of subsequent casualties from cancers and disease.

If it wasn't for an extraordinarily dangerous operation undertaken by firefighters, soldiers and conscripted miners, a second, far more deadly explosion, would have taken place at the reactor, leaving vast swathes of Eastern Europe uninhabitable. It was not only an invisible enemy but an almost invisible story of heroism.

Most authorities now claim that when visiting Chernobyl you're exposed to less radiation than you would be on a long-haul flight. Nobody seems to have told the Ukrainian army this. We go through endless Geiger counter sweeps and detailed inspection of passports and documentation. Finally, we breach the inner 10-km zone and head straight for the concrete sarcophagus in which the reactor was sealed. It was a temporary measure meant to last 20 years.

It is now in its 23rd year so we don't hang about looking at it for too long. For one thing it's not that exciting. For another, our guide's Geiger counter is beeping frantically. We're unsure if this is just to give us a bit of a tourist thrill but we move on sharpish.

Far more extraordinary is the nearby town of Pripyat, just a mile from the reactor, from which 50,000 people were evacuated. But that was not until three days after the accident as nobody bothered to tell them anything until then. It's an eerie place, an overgrown ghost town, a time capsule from the mid-Eighties Soviet Union.

The most poignant building is the school. Books lie strewn around broken desks. Deflated basketballs sit abandoned on the broken wooden floor of the gym. On one wall, posters show the kids what to do in the event of a nuclear attack from the West.

Just one week before the accident the school held a full civil emergency drill in which the children donned gas masks and went down into their bomb shelters. Little did they know that the real enemy was sitting just one mile away from them with most of their parents working inside it.

Drained, we retreated to the town of Chernobyl for lunch. It's about 10km away and some key workers are allowed to stay there for shift periods. It was a relief to get some distance between the reactor and us.

We all washed our hands a little too hard before placing them in a Heath Robinson machine that our guide called a "doseometer". If it beeped green we were clear. Nobody explained what might happen should the machine flash red. We didn't ask: we just wanted lunch and a beer. Atomic tourism is thirsty work.