Afterwards, go down St Martin Le Grand, along Paternoster Row, past St Paul's (think about Paul's Churchyard, centre for Elizabethan booksellers, now home to hydrangeas and lager-swiggers) and down Godliman Street to Queen Victoria Street, savouring the street names and the Wren churches as you go. St Benet is an unusual brick-built Wren church, opposite the splendid 50s wrought-iron gates of the College of Arms. My father was once the vicar here and I heard many a sermon from the Grinling Gibbons pulpit - in Welsh. St Benet's has catered for Welsh Anglicans for more than a century. An earlier church on this site is referred to in Twelfth Night.
Turn right towards Blackfriars Bridge. The Elizabethans crossed the river via London Bridge (which then supported shops and grand houses) or by ferry ("Westward Ho!" shouted the boatman). This bridge, handsome enough, is Victorian and the Thames views are worth savouring. Coffee at Caff d'Arte is recommended just before you cross.
Over the bridge, down the steps on the left near the Express newspapers building, and you join the Thames Walk along Bankside. Pass the power station, more or less derelict, but soon to be a riverside Tate Gallery.
Within minutes, the newest, most impressive building on this stretch comes into view - the reconstructed Shakespeare's Globe - but just before that, spot a narrow 17th-century house bearing a plaque claiming that Christopher Wren stayed here while overseeing construction of St Paul's opposite. Catherine of Aragon is said to have rested here too when she landed in England in 1502. I dutifully noted all this only to discover later, in a booklet about Southwark, that the whole lot is romantic conjecture. But beside the house is an alley which once led to the Cardinal Cap, a tavern where the Globe actors would have caroused.
Pay attention to the magnificent wrought iron gates at the entrance to the Globe complex. Made by local craftsmen, they feature fish and animals mentioned in Shakespeare's plays. Beyond them, the theatre itself. Visit the exhibition and catch a play if you can (only #163;5 for groundlings) to be transported back to Tudor England. Or join a Globe "Walkshop" and find out about the bear-pits and brothels which made this area, outside the jurisdiction of the city, a magnet for fun-seeking Elizabethans.
The walk next takes you past the site of the Clink prison - which provided the slang name for prisons ever after. Here precursors of the Pilgrim Fathers were martyred for their faith and Catholics imprisoned. Gregorian chant sidles up from a dungeon whose entrance is decorated with a decaying "body" put there as a warning to felons. For #163;3.50 (children #163;2.50) you can discover some of the horrors of 16th-century prison life. "Are you a teacher?" enquires the ticket-seller, seeing my notebook. I explain. "Oh TES", she cries, as if referring to a friend christened Tessa, "I'm just looking through mine now." This was a Friday morning. Always good to meet keen readers.
Next door is the ruin of the Bishop of Winchester's House - scarcely more than a couple of stone walls and a glassless rose window - but a reminder of the affluence and power of the Church. The Bishop ran the Clink (there being no other authority) and the local prostitutes were known as the Bishop of Winchester's geese.
A few steps further and a beautiful timber sailing ship hoves into view. This is the replica of the Golden Hinde, Drake's famous pirate vessel, moored in St Mary Overie ("over the river") Dock. A young man in breeches lolls on an anchor. Another approaches wielding a broom. "Are you a teacher?" he asks. (London must be bubbling with eager off-duty teachers planning next term's outings.) This is Chris Saunders, manager of the ship and he shows me over her - the gun deck, the captain's cabin, the pewter tableware, the surgeon's chest of horrid tools, including a handy butcher's cleaver for amputations. He is full of gripping pirate tales and all kinds of information about the ship's construction. He has sailed on her, after all. For #163;30 children can stay overnight and live as Elizabethan sailors. Otherwise, the guided tour is #163;2.30 (children #163;1.50).
Turn a corner and you face the medieval bulk of Southwark Cathedral. Sit down for a minute or two in the cool - there may be a short lunch-time service or an afternoon concert - and then go in search of the splendid red, green and gilt tomb of John Gower, said to be the first English poet because he used the vernacular even before Chaucer did. Shakespeare's brother, Edmund, was buried here and there are memorials to the poet and to Sam Wanamaker whose vision led to the newly-finished Globe.
Outside in the sunshine again, go down Borough High Street and look for a turning under an arch announcing the George Inn. Here you will find London's only remaining galleried coaching inn. Inn yards like this (though much of it has disappeared) once did service as open-air theatres. Anyway, it's a good place to finish and have a welcome drink. London Bridge station is a few minutes' away.
You could probably step out this walk in 45 minutes, or you could spend a couple of days investigating all its possibilities - or continue along the Thames towards Tower Bridge, Butler's Wharf and Kent.