It is an Oxford that has remained unexplored and unappreciated for decades.

The millions of tourists from around the world who are led around the college quads and chapels in the city's Medieval heart are not offered as much as a glimpse of this place.

But all that was to change as I joined a small pioneering group going in search of "Black Oxford".

Well, the uncovering of "Black Oxford" was what was promised in the publicity material, advertising a ground-breaking new walking tour of the city centre. Although, as I suspected, the "Black Oxford" that we are now being invited to discover is actually limited to Oxford University's black heritage, rather than the city's.

But it is apparently something that has never been properly celebrated until now (save for a rather good exhibition at the Oxfordshire Record Office in St Luke's Church, Temple Cowley, two years ago).

Thanks to a £45,900 Lottery grant, a series of walking tours have been organised to ensure that "the untold stories" of black people and the part they played in the history of the university are fully explained.

The walks are taking place every weekend until the end of October to coincide with Black History Month. They are expected to begin again next year. At least we must hope so, otherwise each walk, led by volunteer guides and costing £5 a person, will have proved very costly indeed to the Lottery.

But before anyone starts to wonder if the cost of each walk is going to have worked out at £3,000 a go, it must be pointed out that the Lottery money should eventually fund a permanent Black Oxford exhibition, with a special DVD also being produced.

Either way, joining the very first Oxford University Black Heritage tour promised to be something special - and it was to be, in its way, quite unforgettable.

The idea behind the tour is that, for too long, guides and visitors to Oxford have been invited to concentrate on the likes of C.S Lewis, Lord Nuffield and Harold Macmillan.

Why do we not get to hear about some of the black figures who attended the university, such as John Kufuor, the president of Ghana, and Raymond Robinson, prime minister of Trinidad and Tobago?

The tour is the brainchild of Pamela Roberts, founder and executive director of Artistry Events, a non-profit arts group.

She explained: "Oxford University has attracted and produced many of the most original thinkers over the past several hundred years. On any official tour here, you can hear about the history of the colleges and the famous alumni - Tony Blair, Bill Clinton, Margaret Thatcher - to name a few. But what about the black scholars?"

"Oxford University has had many African and African Caribbean students pass through its colleges throughout history and the new tour will shed light on their untold story. It will promote Oxford's black presence and its contribution to the wider society and showcase the city's diversity."

Rather unnervingly the a press release asks: "Did you know that Raymond Robinson, prime minister of Trinidad and Tobago attended St John's College. What about the contemporary jazz saxophonist Soweta Kinch, who has a degree in Modern History from Hertford College?"

And there was I feeling clever because I can point out that Lawrence of Arabia was an All Souls man and Hugh Grant went to New College.

Ms Roberts is best known in the city as the main driving force behind the award-winning International Black Media Festival in Oxford, which was staged for the fourth year at the beginning of the month. Earlier in her career at the BBC, she established the corporation's first broadcasting unit.

It turns out she was inspired to create the walk while sitting outside enjoying lunch on a sunny afternoon in Oxford.

"I was watching the tour guides in the city centre," said Ms Roberts. "It just struck me that you do not see any black people doing it. It led me to make inquiries about whether there were any black walking tours.

"When I first began looking into I was told, 'black people didn't go to Oxford University. They came here in the 1960s and went to Cowley to work on the buses'."

The response infuriated her and after setting herself the task of discovering everything she could about black scholars, she was delighted to find black people had in fact been studying at Oxford for about 130 years.

"It struck me that the tours on offer are all about colleges, and how they came into being," she said. "What we are going to do with Black Oxford is concentrate on the actual people."

Happily, for Ms Roberts, her initiative not only appealed to the National Lottery but Oxford University as well. For it tied in nicely with their various initiatives aimed at increasing applications from under represented groups. The university had even launched a scheme with the unlikely title 'Black Boys Can' at Oxford, in partnership with the student-led Oxford Access Scheme, which brought 40 black British boys and their parents from inner city areas to Oxford in August to experience what the university has to offer.

A big party to launch the walk was held in the grand surroundings of the university's Museum of Natural History, with the press conference hosted across the road at Keble College.

Keble is one of the key spots on the tour, for the college can count among its alumni one of Oxford's black heroes, the wonderfully-named Lushington Wendall Bruce-James.

Born in Antigua in 1891 and brought up in British Guiana, he went up to Keble College in 1910 and took a third in Classical Moderations. He was to serve in the University and Public School Corps of the Royal Fusiliers in the Great War and later embarked on a musical career in London.

But Christian Frederick Cole, a student from Sierra Leone, was almost 40 years ahead of him.

Cole's charm and determination in the Oxford of the 1870s proved that black people could aim for the same academic standards as the most privileged young Victorians.

He attracted enormous attention at the university before being called to the Bar in 1883 and going on to become the first black African barrister in the English courts.

Black barristers figure prominently on the tour, offering guides the opportunity to indulge in accounts of murder trials.

Another wonderfully-named character, Edward Theophilus Nelson, who graduated from St John's College in 1902, was to enjoy lifelong fame by successfully defending a white man accused of murder in the 1909 Stalybridge Murder Trial. Ten years later he successfully defended African dockworkers accused of rioting in Liverpool.

Glancing at the tour itinerary, however, it becomes increasingly apparent that household names are pretty thin on the ground.

Jesus can certainly lay claim to a couple of political heavyweights.

A portrait of Norman Manley - the former Jamaican prime minister who was prominent in the struggle for independence - hangs in his old college.

Pixley Seme, the co-founder of the African National Congress, was also a Jesus man.

Then there's Edward Akufo-Addo, president of Ghana (St Peter's College).

But my guess is that the likes of "cultural theorist and intellectual" Stuart Hall and Rex Nettleford "the well-known Caribbean scholar, trade union educator, social and cultural historian" will be for specialist tastes.

Sadly, the two figures to make the ears prick up, Desmond Tutu (who collected an honorary degree in 1990) and Malcolm X (who spoke at the Oxford Union in 1964) were only here on the briefest of visits.

So, with appetite whetted at the press conference, a small press corps was taken to Broad Street for the epoch-making first black walking tour.

Sadly, the guide had already set off, leaving embarrassed organisers to apologise for a misunderstanding.

I eventually found her standing on the pavement outside St John's, struggling to make herself heard over the sound of roadworks as she read an account of the career of Edward T Nelson. Uninspiring, but worse was to follow.

The guide's refusal to be photographed on what was a press launch ("Nobody told me there were going to be cameras.") resulted in me having to seek the intervention of Ms Roberts, looking proudly on outside Balliol. By the time I returned the first historic walking tour had already gone.

My search for Black Oxford had ended in the rain outside a Broad Street sandwich shop, where I pondered on whether one day there would be Indian, Pakistani, South American, or even Irish, university tours.

It was to prove an ill-fated weekend all round. The Sunday walk was to be cancelled when the guide failed to show up, while on Saturday there had been something of a 'mutiny'.

The guide had been showing around a group of children from Tottenham, but half-way through he was told in no uncertain terms that the youngsters had a more pressing priority.

He explained: "The teachers said that what they really wanted was not an austere take on black history, but to see Christ Church, where Harry Potter was filmed."

But how could it be otherwise? The children from London might have been black - but that did not mean the Oxford of cultural theorist Stuart Hall was going to be more interesting than Hogwarts.