And on your right, the site of the Morecambe slave boy's grave

Forget the medieval castles, British history has a darker side. Alan Rice embarks on an alternative UK study trip.

The European Grand Tour has been a staple for American tourists ever since the late 19th century. The British leg usually involves visits to medieval castles, Shakespeare's birthplace and Wordsworth's cottage, with accommodation in Oxford Quads or stately homes an optional extra. Since the second world war, American colleges have continued this tradition through study trips. These tours promote Europe as the home of European civilisation and history with a capital "H".

Such visits have great educational value, serving to inculcate insular American teenagers with an expanded world view. The tours have remained largely unchanged over the past 20 years, despite massive changes in American university humanities curricula. English and history syllabuses have expanded to foreground contributions by non-whites, women and the working class, yet the tour is still mainly the preserve of famous dead white men and royal palaces.

In light of this anomaly, Angela Leonard, a history professor at Loyola College, Baltimore, recently led a British tour specifically designed to look at the underside of British political, social and cultural history: its involvement in the slave trade. Leonard wanted her students to visit places that challenged ideas of a homogenised British past. She also wanted to broaden their knowledge about the African diaspora and its ramifications for African-Americans and to celebrate the existence of people of African origin in Britain through the centuries. And, through visits to less well-known slave ports such as Whitehaven and Lancaster, she hoped to show her students the ubiquity of slaving in Britain and its continuing legacy for British people.

At Whitehaven, where the tour began, the students and I visited the newly opened Rum Story exhibition, which shows how rum, so central to Whitehaven's wealth and development, was made by slaves in the Caribbean. The exhibition makes great play of the realism of its exhibits, including a replica slave-hold that smells of human excrement. It was a lesson in the harsh economics that buttressed the development of the British economy. We also visited a more traditional site, nearby Dove Cottage, but heard not only of the Wordsworths but also of the man whose portrait adorned the staircase, Thomas Clarkson, whose agitation helped to end the slave trade.

The evening was spent discussing a dramatic tableau about 12 key characters in the slave trade and their movement around the "black Atlantic". It showed that those who mostly stayed put -including absentee planters, slave traders and merchants' wives -got richest. The students also learnt about the transatlantic side to the lives of African-American heroes such as Frederick Douglass and Harriet Jacobs whose internationalism is sometimes forgotten in traditional American historians' accounts of their importance.

Unable to visit "Sambo's Grave" in its lonely exclusion at Sunderland Point near Morecambe because of the foot-and-mouth epidemic, we were shown the original 18th-century grave marker that commemorated this boy's premature death in 1736, a continent away from his home, in a Lancashire port in which he had spent only two days. The students could only wonder at the emotional impact of Sambo's exile as a visit to the lonely spot sends shivers down the spine. This site brings history to life and explains the dispersal of people in a deadly trade better than any museum exhibits.

Lancaster proved a very rich experience for the students: a visit to the Judges' Lodgings emphasised how even the most mundane objects and materials were implicated in the slave trade. As curator Stephen Sartin described the wonderful Gillows mahogany furniture that adorns the rooms, he explained the importance of the mahogany trade in the slave system. It was the crucial raw material brought back from Jamaica by Lancaster sea captains on the third stage of the triangular trade and proved vital for the economic development of Lancaster in the 18th century.

After an afternoon of lectures at the Lancaster Maritime Museum, which, as a Customs House, played a pivotal role in the slave trade, the students were given a presentation by Zanzibar-born Lubaina Himid, reader in fine art at the University of Central Lancashire, about how her work is influenced by the slave trade. She spoke of the need to "make monuments" to those who died en route to the slave plantations, showing students how slavery survives in the imagination of contemporary black British artists.

In Liverpool, the students visited the comprehensive Slavery Gallery at the Merseyside Maritime Museum before attending lectures. The highlight of their Liverpool trip was a guided tour of the city by Eric Lynch. Slavery imprinted on the architecture of the city and buildings tells a story not of imperial grandeur, but of exploitation. A slave ship was even depicted on a church.

By the time the students got to Bristol, they were skilled exhibition readers. They were disappointed that the slavery exhibit there, now housed in the Industrial Museum, seemed to concentrate on negative images of diasporan Africans. Curator Sue Giles was surprised at their observations, which had not been made by British students and showed their transatlantic perspective.

On the last day of the tour, at the National Maritime Museum in Greenwich, Robert Blyth showed us the exhibits on slavery in the empire and trade galleries. His retelling of the controversy at the gallery's opening in 1999 over the tableau of a manacled black hand coming out from a hatch beneath an English lady drinking tea showed how many British people still refuse to acknowledge the link between "refined" English culture and slavery. In the wake of the criticism, the tableau was withdrawn. For Blyth, this was not a disaster as "the tableau had done its job" by the controversy it generated.

For us, it seemed that censorship had won through and that elements of the story were being denied us. But then, the controversial nature of the history of the slave trade means that representing it will always be problematic.

Ultimately, what this multi-faceted study tour showed was that telling the story from as many angles as possible, through lectures, site visits, walking and museum tours, meant that students were given the tools to make up their own minds. Maybe universities in Britain can learn a lesson from tours such as that undertaken by the Loyola students: that there is a place even in the humanities for extensive field trips, and that the study of topics such as slavery becomes far more illuminating when moved out of the classroom and the library and into the contested spaces beyond the university's walls.

Alan Rice is principal lecturer in American studies and cultural theory at the University of Central Lancashire.