BERLIN, Germany -- I'm in the heart of Berlin, sitting behind the wheel of a small and gently throbbing 1960s vehicle once widely considered a symbol of freedom. But suddenly a voice crackles from the dashboard speaker. "I talk, you listen!" it barks. "Just like in the old communism times."

The man at the microphone is only Jordi of Trabi Safari, the guide in the leading vehicle of a convoy of rattletrap Trabant cars. He merely wants to make sure we remember the rules of the road before we brave the boulevards of Berlin. There's no turning at a red light, and we must always give way to Berlin's plentiful bicycles. There's no smoking in the car, and the ashtray contains a phone number in case anyone gets completely lost.

"Don't try to look for us," Jordi says. "We're still missing one guy from yesterday."

Everyone laughs. But perhaps the missing driver was misguidedly still trying to escape to freedom.

In May 1989 communist Hungary unexpectedly opened its border with capitalist Austria, and East Germans on holiday there seized the opportunity to escape to the West. As the news spread and long lines of Trabis emerged from behind the Iron Curtain, these little cars -- the summit of East German consumer technology but decades behind the West -- were seen by television viewers around the world as symbolising both the desire for freedom and its attainment.

I've already been given an introduction to the rather limited controls of my Trabi.

"The most important thing is the horn," I'm told. "Clutch, brake, gas, are like a normal car."

More importantly, what isn't like a normal car?

The gear-stick protrudes from the steering column along with the control for the indicators, which are not self-cancelling. Column shifts were common in the 1950s when the very first Trabis were built, but although there were later modest revisions to a body shell made from cotton and chemical resin, there were few other changes over the following decades.

"Wave out of the window if you can hear me, please," Jordi says.

We all wave, and we're off.

Pulling out of the lot we have to wait for gaps in the traffic so we're quickly split up, but swiftly reform again.

I'm trying to overcome the habit of reaching in entirely the wrong direction for the gear stick, and trying to remember to cancel the indicators, which have neither a flashing dashboard light nor any audible click.

The speaker pours out details of the buildings we pass, together with instructions to keep together. The brakes are spongy but the pace is modest, and the gearbox is surprisingly smooth, as long as I remember to pull the stick out a little for third gear. This is only finally attained when accelerating through one traffic light, but I'm caught at the next.

"Keep on going straight ahead," Jordi says. "We're going to wait for you."

While a couple of drivers behind have opted for "classic" Trabis in their original drab green or pale blue, in front of me is a fanciful bright red open-top stretch-limo version with two backwards-facing seats. My own vehicle has been repainted as a leopard and another is disguised as a zebra. Pedestrians give us a wave, and whenever we stop at lights we are photographed and filmed by other visitors. We're not just viewing the city's tourist attractions; we are one ourselves.

We pass Third Reich administration buildings such as Hermann Göring's handsome Ministry of Aviation (miraculously unscathed by British bombers), several famous ancient churches and palaces, and the place where Berlin was founded in 1237.

Sometimes we rattle over ancient stone paving, all too aware of the Trabi's slightly unforgiving suspension system. But the car really comes into its own back in its home of East Berlin, where the broad boulevards that seem essential to communism everywhere allow us to race along in fourth gear. We speed past the long, low frontages of severe apartment blocks hung with dated neon signs of sham glamour advertising the shops below.

"If we carry on driving down here in a couple of thousand kilometres we'll be in Moscow," Jordi says.

From the look of the architecture we might already be there.

As with most other aspects of life in East Berlin at the time, these facades were just a facade -- a pretence that a planned economy could deliver just as many benefits as the freewheeling capitalism a short distance away in West Berlin. But the apartments on each floor shared a single lavatory, and there was no central heating, we're told.

"These are short lights so get in first gear and we can all cross together," Jordi instructs. As they change to green he accelerates away at such a rate that his vehicle briefly disappears altogether behind a cloud of exhaust.

It's hard to believe that there are still more than 30,000 of these machines sharing the roads with famously well-engineered Mercedes, Audis and BMWs. Their twin-cylinder, 600cc, two-stroke engines burn a polluting mixture of oil and gas, and are mostly banned in central Berlin.

Many who escaped East Germany by Trabi simply abandoned their vehicles on arrival, and in 1989 they could often be bought for little more than the price of a bottle of beer. After reunification an attempt was made to save the Trabant company by fitting the car with a proper Volkswagen engine. But there were no funds to redesign the body, so in 1991 the company closed. Now nostalgia means the tinny little vehicles command the euro equivalent of $1,500 to $2,000.

But in 1989 the lines of Trabis at the Austro-Hungarian border marked the beginning of the end for the communist-ruled German Democratic Republic. Six months later joyful sledgehammers were reducing the Berlin Wall to rubble and shortly afterwards Germany was reunited as one country.

The often comical commentary and the sheer fun of mastering an archaic vehicle while taking in the sights makes for a hugely entertaining excursion. And how better to celebrate the 25th anniversary of the fall of the Berlin Wall than to drive freely back and forth between East and West in the cars that led the way?

MORE INFORMATION

-- Trabi Safari, a few minutes' walk from city-central Checkpoint Charlie, offers a choice of self-drive tours lasting one or two hours.

-- The company's newly opened Trabi Museum, just nearby, tells the history of the vehicle with an excellent display of Trabi variants from 1954 onwards, including police and army versions, and a racing version capable of up to 192 km/h.

-- As an alternative without the pollution, consider Berlin on Bike. The city is flat, its traffic courteous, and the company's guides articulate and well-informed about the history of the city, and of the Berlin Wall.

-- For more on the Berlin Wall, go to this page on the Visit Berlin website: mauer.visitberlin.de/en/.

-- For travel information on Germany, go to the German National Tourist Office website at germany.travel.