What do you do when you’re stuck in heavy traffic on Whitehall with a bus full of primary pupils? Sing “Happy Birthday” to your tour guide: at least this is an option if your tour guide is Baron Belching of Burpsworth, who is, he claims, 777 years old today.

The Baron is the archetypal pantomime villain; his sidekick is Felicity Phartley of Fairweather, a traditional pantomime dame. They introduce groups of schoolchildren to the history of London with a theatrical slant, starting backstage at the Old Vic and ending with a view - but only a view - of the restored Shakespeare’s Globe. The idea for the Buzz Bus (a purple double-decker converted into a travelling theatre) came from Claire Rooney, an entrepreneur who has worked in PR and catering. Rooney and her friend Stacey Elder, a former actress and drama teacher who has worked in theatre in education, decided to provide something they hadn’t found on offer in London: a guided tour for school groups which would entertain as much as it informed.

Elder and Rooney trailed round many depots before finding a suitable double-decker in Sheffield. They refitted the interior and created two performance areas, one on each deck. They even found space for a box office. The result must be one of the most inventive resources available to schools that want to enthuse key stage 2 and 3 pupils about history, English literature, drama or all three. In the long term, Dublin, Manchester and Edinburgh might be added to the itinerary.

I catch the bus with some of its first passengers, Year 3 and Year 5 pupils from St Mathew’s primary in Westminster. First stop is Waterloo and the Old Vic, where an elegantly dressed usher (played by the same actor as the Baron, Theo Van Dort) escorts us backstage. We hear how the Royal Coburg Theatre (opened in 1818) was renamed the Royal Victoria Hall in 1833 in honour of the then Princess Victoria, how the top gallery in the auditorium was removed in 1845 after members of the audience were crushed to death in the panic caused by a suspected fire, how Lilian Baylis made the theatre “The Home of Shakespeare” (“Quest for Shakespeare” is the theme of the tour). After a roll-call of the theatre’s great names (Sir Laurence Olivier, Dame Edith Evans, Kevin Spacey and various ghosts) and a swift on-stage warm-up workshop, we are back on board.

Enter the Baron and Felicity (today played by Derek Newbury; the BuzzBus has a team of six actors, all with Theatre in Education experience). The quality of the acting is crucial, and Van Dort (top deck) and Newbury (bottom deck) work extremely hard in their well-judged roles. Their double-act, which involves much banter, audience participation and heckling, is audible on both decks at once. The part-improvised, part-scripted dialogue is laden with wide-ranging historical references: we take in the Battle of Trafalgar, Christopher Wren and St Paul’s Cathedral, the 1665 Plague, the Great Fire of London and Guy Fawkes. There’s a mention for the sinking of the Titanic as we pass the building just off Leicester Square where tickets were sold. However, the facts are not delivered in chronological order or with any sense of the developing story of a city. Instead, each landmark is a trigger for a new piece of information.

At pound;7.50 per pupil (a minimum 40 children per booking), the two-hour journey (including half an hour at the Old Vic) seems good value as an interesting diversion for pupils, although the sheer volume of information delivered by the actors is likely to test pupils’ powers of retention. There is a questionnaire to fill in out on the way back to school or use in class later, and the experience will certainly reinforce what pupils already know. The Year 5 group has read A Midsummer Night’s Dream and studied some of the events mentioned from the Tudor period.

The actors respond well to requirements for improvisation (killing time in heavy traffic, for example) and to the pupils’ level of attention. After a dull stretch down Fleet Street (we are told about the street’s media connections but little else) they involve everyone in producing sound effects for the Great Fire of London.

The Shakespeare theme (the basic premise being that Felicity and the Baron are in search of the Bard) is underdeveloped. Shakespeare himself (actor Raymond Brookes) canters through his complete works in rhyming couplets on audiotape. We join in with the “Bubble, bubble, toil and trouble” speech from Macbeth and sing along to “Brush Up Your Shakespeare” from Kiss Me Kate, but the closest we get to the Globe is the view from Southwark Bridge, where the guides, as they hop off the bus, tell us: “We have found Shakespeare.” Surely this is a missed opportunity?

The Buzz Bus: 020 8878 3450. Door-to-door service for schools in London; afternoon pickups from central London locations can be arranged for schools from further afield