Billingsgate started trading in the shadow of London Bridge, some 1,200 years ago. At first it was a small port where general cargo was unloaded and traded. By the late 4th century, this port-cum-market gained the exclusive right to sell fish, with the powerful patronage of the Fishmongers’ Company and the Corporation of London. In 1372, Edward I (currently better known for stealing the Stone of Scone from the Scots) granted Billingsgate a charter to supply fish to London and its environs. The Fishmongers’ Company, one of the original 12 great Livery Companies, along with the Corporation, still runs the market under the same 700-year-old charter.

Billingsgate transferred to the Isle of Dogs in 1982, because of chronic traffic congestion and no room to expand. It now occupies a 13-acre site overlooked by the towering Canary Wharf building and is served by the Dockland Light Railway. The market is a remarkable success story that provides a rich and living example of an ancient institution that has moved with the times but kept the best of its past.

The recent national curriculum report on the teaching of design and technology stressed broad, balanced and relevant practical work which leads to a better understanding of business and industry. Worthing High School is a mixed comprehensive by the coast of West Sussex. Its staff are seasoned school visit veterans with four previous outings to the Docklands’ market (plus other London businesses) under their belts. Clearly, they have found such visits both useful and enhancing to their teaching and see them as an integral part of the school’s annual enrichment week, held in July, after most exam commitments are over.

“The key,” says design and technology teacher Bernadette Wright, “is thorough preparation. I strongly recommend a reconnaissance trip to sound out potential learning and curriculum opportunities.” She was speaking soon after their coach arrived with three other colleagues and 16 boys and girls from Year 10. It was a few minutes after 6 am.

In the brightly lit trading hall, Sergeant Phil Read, in charge of the 12-strong special constabulary who police the market and act as market guides to visiting groups, explains the rules: “Wear non-slip, preferably waterproof footwear, because the floors are regularly sluiced down with water. Look out for porters’ trolleys charging up and down. They have priority because they’ve got a job to do - they’re paid by the size of their load. Also, it’s not easy to turn or stop a trolley carrying up to 60 stone of fish!” Trading officially starts at 5 am, which is why it is necessary to be early.

Down on the selling floor, it’s confusing and noisy. More than 300 white-coated and hatted traders and porters are shouting and making deals. There is quite a bit of colourful language both from porters clearing the way for their trollies and from salesmen bargaining prices with customers. One market administrator, David Monger, is quick to defend his colleagues: “It’s a tradition even Shakespeare knew about. I believe there are several references both in his plays and in contemporary cartoons to the foul-mouthed fishwives who accompanied their porter husbands to the market. Now porters are officially forbidden to swear and we have very little trouble from them.”

Mr Monger then produced an enormous and ancient record book which lists all the porters hired over the past 100 years, thus reinforcing the sense of history and tradition which trickles over every slippery yard of the market. He then points out two names penned in scratchy copperplate - Joseph and Maurice Micklewhite - father and uncle of film star Michael Caine.

On another page he indicates a certain Joseph Barnet, apparently the commonlaw husband of one Maria Jeanette Kelly, the last tragic victim of Jack the Ripper.

Coming downstairs to the trading area, three of the pupils quickly get into the spirit of things by trying to negotiate a lower price for a sack of whelks. The visits are absorbing lessons in many subject areas - maths, geography, history, environmental studies, design and technology and economics.

Some stop to to look at what the market calls exotic fish, but Peter McCoy of Sudders Ltd calls the “ethnic market”. He was the first to realise the new immigrants arriving in Britain during the 1950s and 1960s from the West Indies, China, Asia and Africa would create a demand for hitherto unknown varieties. So keen was he to meet their needs, he learned Chinese. Now, fish such as the giant bluefin tuna are a common sight at the market.

The last part of the tour took them into an enormous cold store which keeps nearly half the merchants’ total stock at -28 C. Store manager Tony Forrester considers it one of the best in Europe. His revelation that he was a more of a Eurosceptic than Teddy Taylor created another teaching opportunity - politics and economics.

Call the market superintendant’s secretary on 0171 987 1118 or write to: Billingsgate Fish Market, Trafalgar Way, London E14 5ST. Only pupils aged 12 or over are admitted