Once inside, the monotonous drone of the guide proves too much for even the most stalwart of sightseers, which none of this group is. One of the boys, his mind wandering from the wooden recitation of historical dates and events, catches sight of a beautifully-crafte d medieval font. “Hey look,” he shouts to his mates across the vast hall, “an ashtray!”

“Shuddup” is the response from a few of his voluble colleagues.

A typical school trip? Well, yes and no. While their behaviour is not particularly unusual for a group of 12 to 17-year-old boys, being on a trip so far away from home is. The 10 lads and their teachers are from the Heath School in Colchester, Essex, a boarding school for boys with emotional and behavioural difficulties. It is the first EBD school ever to take part in an exchange with a Czech school.

With or without an exchange, it is rare for an EBD school to take pupils abroad. The anticipated difficulties of keeping the children in check, the careful planning to ensure safety and avoid boredom and the prospect of dealing with unforeseen but likely behaviour problems all act as disincentives. Taking them to somewhere as far-flung as the Czech Republic is even rarer. This is not western Europe we’re talking about but a country which, until seven years ago, suffered the same shortages and inefficiencies as all other Soviet satellite states. In some ways, things haven’t moved on. And in other ways, it is a very different place to what it was before the Velvet Revolution elegantly booted out the Russians and installed its then beloved dissident poet Vaclav Havel as president.

Whatever condition the Czech state is now in, as far as the intrepid staff of the Heath School were concerned, the visit was an opportunity not to be missed. It all started two years ago, when about a dozen children in the dyslexia unit of the Zakladni School on the outskirts of Prague came to Colchester. The Heath School was asked at the last minute by Essex County Council if it would host the boys and girls. The school complied graciously and, in the process, made friends for life. So when the EBD school was invited to Prague on a reciprocal visit, it was taken up with pleasure.

And with careful planning. First, money had to be raised. Although all the living expenses in Prague would be taken care of by the Czech school, the 10 boys had to get there. The cheapest option was travelling with a commercial coach company, costing #163;65 each child and #163;80 each adult.

The school wasn’t prepared to ask parents (or in some cases, the local authority) for the full amount, so they set about fundraising for the boys’ fares and a pre-trip visit to Prague by acting headteacher David Baker for planning and liaison with the Czech school. They raised #163;600 from the British Council and #163;1,000 from staff at the local McDonald’s. A local pub contributed, too. In the end, each boy had only #163;25 to pay, plus #163;20 spending money, which was held and doled out by the teachers on request. It was a testament to them that all the wheedling and needling once boys’ money ran out didn’t lead to a single harsh word.

David Baker had to plan things carefully with Yaroslava Skvorava, the head of the dyslexia unit at the Zakladni School, to ensure that at least as important as ensuring the boys’ comfort and safety was organising things so that they didn’t get bored. An itinerary was devised that had them out and about doing a mix of sightseeing and sporty things. David Baker checked everything out on his preliminary trip, even arranging for Steve Whitfield, a teacher who was to accompany them, to take a lifeguard course since the local swimming pool didn’t offer such luxuries.

The painstaking planning paid off. Sure, things went wrong. On the first night, one of the older boys managed to acquire, consume and get legless on a half a litre of vodka. It’s not difficult to do in a country where it costs the equivalent of 86p a bottle and is there for the asking.

Then there was the 21-hour coach journey. Going there was a doddle. But heading back home, the air conditioning wasn’t working and a couple of the boys got claustrophobic in the stifling heat, went a bit bananas and had to be restrained. In between, there were small irritations to do with a shortage of toilet paper and inevitable complaints about food (which was fine if you really liked eating meat, dumplings and sauerkraut every night). Oh yes, and the frustrations and tensions that are part and parcel of a bunch of boys of various ages having to sleep together on camp beds in a classroom masquerading as a dormitory for their benefit.

Not to mention the discrepancy between the Czech teachers’ idea of fun and discipline and the Heath’s. David Baker explains: “Because the exchange was with a dyslexia unit, there wasn’t a great understanding of what emotional and behaviour difficulties meant. Maybe because of having grown up under an authoritarian regime, the teachers had different expectations of our kids. They believed that if we were strict enough with them, they’d behave. But it was a good thing, being under the pressure of their expectations.”

Because they knew their boys, Baker and Whitfield also had to diplomatically re-jig certain bits of the planned schedule. “Because of the boys’ attention span, we had to cut all the activities by 50 per cent - or more. For instance, they wanted us to spend all day in the classrooms with their kids. When we realised this, we negotiated it down to an hour, which caused some offence. But we knew that it wouldn’t work.”

The fact that the exchange trip was such a success was certainly due to Baker’s and Whitfield’s understanding of the boys’ needs, desires and thresholds of tolerance. The fact that the Zakladni School is located smack in the middle of a bleak, post-Stalinist-style housing estate an hour’s bus ride from Prague with virtually no amenities meant that they had to cleverly ration the time they spent at their home base.

So they got around, sometimes on public transport, sometimes using the Czech school’s minibus, sometimes riding in the cars of Zakladni parents. They went to Prague Castle, to the beautiful Old Town Square, to a swimming pool and to Konopiste Castle, 30 miles from Prague, where the boys licked their chops as they viewed one of the biggest collections of armoury in Europe, owned by the ill-fated Archduke Franz Ferdinand. In the grounds of the castle, boys were allowed to perch falcons on their arms - a major feat for the more fearful ones - and later cooked sausages on a wood fire, #224 la Czech. Just being outside, free to gambol in the woods,was a first for many of them.

On the last night, the Heath group laid on a party for the Zakladni children, teachers and parents at which a couple of the boys danced with girls for the first time ever. That the trip was a positive experience for everyone is beyond question, in David Baker’s view. “The biggest thing was going somewhere with a very different culture. The boys liked being with the Czech kids - particularly the girls - and generally met the high expectations that were being made on them.”

An unexpected highlight for the teachers was being given seven tickets for a Beethoven concert by the Czechs - an offer that they couldn’t refuse.

“We wouldn’t have even tried it out if we hadn’t been forced into it by the Czech school, ” admits Baker. But he was in for a surprise. “It was brilliant,” he says. “Although some didn’t like it, including one boy who started testing the tunes out on his new digital watch and another who talked loudly throughout, the others accepted it as a new experience and behaved respectably.”

The Heath is hoping to set up a three-way link with the Czech school and a French school next summer with the help of a special European Community fund to foster cultural links between young people. Whatever shape the next stage takes, the Essex boys at this EBD school are going to be very much of this world from now on.