And to your right you can see the Gallions Hotel, where Rudyard Kipling stayed before he sailed for India...”

I followed the gaze of Natalie Osei-Owusu, our cheerful guide, across the dual carriageway to the sad-looking building standing forlornly in a scrubby wasteland. It was difficult to imagine it as a bustling staging post for 19th-century colonialists and adventurers, including the famous author of The Jungle Book.

Just as it was impossible to picture St Mary Magdalene, the Norman church we had passed a few minutes earlier, in its heyday in the 11th century, given that it now stands somewhat apologetically in the shadow of an A13 flyover.

But there are many uncomfortable juxtapositions caused by unsympathetic civic planning in a part of London so run down that it took the promise of a $1 billion cheque from the International Olympic Committee (IOC) for ministers to take proper remedial action. Through the windows of this London tour bus, the sights did not include Buckingham Palace, the Houses of Parliament or St Paul's Cathedral but a derelict slag heap, a disused asbestos-laden flour mill, the depository for most of London's sewage and the biggest building site in Europe.

Welcome to the most unlikely tour of London, taking in parts of one of the world's most visited cities that you will not find in the glossy brochures. This is forgotten London. At least it was, until the East End became the stage for the 2012 Olympics, the biggest spectacle in sport.

With the party in Beijing over, there are no more distractions. London 2012 is next, and it is an equally exciting and sobering prospect. The spotlight is bringing a new breed of visitor to one of the most socially deprived areas of Britain, which is about to be transformed after a century of economic neglect. Take the “regeneration tour” of Newham, the borough most touched by the Olympic Park. The meander through a decidedly edgy part of London used to be a chore for community leaders, a duty for potential investors and a time-filler for people with nothing better to do on a Wednesday morning.

But, on the back of Britain's barnstorming performance in Beijing, where the Olympic team won 19 gold medals and the Paralympic athletes brought home 42, it is becoming a must-see.

The regeneration tour, basically a showcase for the council's urban improvement projects, is booked up to two months in advance and has attracted people from as far afield as Russia, Japan and India. It is easier to get a seat on the London Eye.

“We want to show tourists that this isn't the place they think it is,” Sir Robin Wales, Mayor of Newham, said. “We think we have the most amazing place coming up.”

If you are not a local resident, for whom the tour is free, it would be cheaper to buy a ticket for a West End show. Depending on the clientèle, the tour can cost anything between £200 and £400.

Since June, there have been more than 200 requests to visit the Olympic Park Viewing Gallery in Stratford. It is essentially a Portakabin plonked on the roof of a 1960s tower block, yet it has hosted the Queen, Willem-Alexander, the Crown Prince of the Netherlands, Gordon Brown and the actors Sir Michael Caine and Sean Bean.

Such is the interest in the evolution of forgotten London, and the investment opportunities, that companies are prepared to pay £250 to overlook a new Eurostar terminal and a vast building site.

So, putting the mayor's claim to the test, I boarded the minibus at Newham town hall - a Grade II listed Edwardian building - to see the parts of London that I had never really wanted to reach. We soon came to Beckton, a slag heap locally dubbed “the dumps” that someone once thought was a good place for a dry ski slope. Since its closure in 2001, the mound, aka Beckton Alps, has lain derelict with vague plans to build a 140-room hotel in its place. A salutary lesson for Olympic planners, perhaps? But there was little time to dwell as we learnt that Beckton, named after a 19th-century gas tycoon, was famous for being the final destination for all London's sewage generated north of the Thames. Things could only get better. Surprisingly, they did with my first visit to the Thames Flood Barrier and a free cappuccino on the council's tab. I have lived most of my life in London, albeit southwest, but have never seen the defence that has saved the city from flooding more than 100 times over the past 30 years.

I was able for the first time to question my fellow tourists. Why on earth were they here? For Trevor Lingwood, a retired electrician, and his wife, Dorothy, who now live in Essex, the reason was to indulge in some nostalgia. “This area has changed so much. It all used to be marshland,” says Lingwood, whose father was a shipbuilder and whose mother worked in the Tate & Lyle factory before she was evacuated to Somerset in 1940 to give birth to him. The family returned after the war. The others were simply curious. Dipika Patel, a volunteer worker from Newham, was interested in local history and Errol Richards thought the tour would be a good way to get to know the area after moving from Battersea. Janet King and Anne Larrion, from East Ham and Stratford respectively, wanted to find out how their taxes were being spent, particularly with regard to the Olympics.

On the Victoria Docks footbridge, the architectural follies of the recent past started to make a bit more sense in the new framework of 2012. From here we could see the Millennium Dome, renamed the 02 Centre and now a thriving live music venue, which will host the gymnastics and basketball during the Games and the ExCel Centre, which will house wrestling, fencing, table tennis, judo, tae kwon do and boxing. And in the distance is City Airport which, with its 10-minute check-in time, will provide athletes and spectators with an easy entry-point to Britain from contin- ental Europe.

“With the world's focus on us, it gives us an opportunity to show what we've already got going on here,” Larrion says. “We can see improvements all the time.”

Because of their proximity to the airport and Eurostar, the docks could become a hub of commerce if planners get the mix right. On a windswept and grey weekday morning, it is difficult to picture the place bustling with people, but more than 500,000 a day will visit the area over three weeks during the Games.

With that much traffic, there must be a tangible impact. Local politicians hope the experience will be enough of an eye-opener to result in East London being added to the tourist itinerary so that more outsiders can learn about the area's rich history.