At breakfast, on the first morning in Venice, I had a Mr Toad moment. Gazing out at the endless craft drifting up and down the Grand Canal, I was seized, mid-croissant, by a sudden vision: I saw myself at the helm of my own little boat. If I could rent a scooter in Rome, and a horse in Mongolia, then why not, in Venice, a boat? Dizzy with new enthusiasm, I rang the tourist office for advice. They sounded a trifle startled when they understood I intended to drive the boat myself, but after some hesitation, they faxed me a list of boat agents. I telephoned the first one and booked a boat, as simply as if it had been Hertz Rent-a-Car. Poop, poop, I murmured, gazing out at the water.

The following morning I found the boat office just off the Grand Canal on the Fondamenta Labia. The boatman took me outside to show me over my craft, a handsome green boat nestled between the mooring poles and the quayside. It was about 12ft in length and had a small out-board motor.

It was at this moment that I remembered that I had never actually driven a motorboat before. Concerned that the boatman might see this as a reason not to let me loose in Venice, I gave a performance of nautical knowingness, nodding sagely as he pointed out lockers and ropes. When I explained that English motorboat engines were different to Italian, he showed me how to start and stop the engine. For the rest, I would trust to luck. How difficult could it be?

I got away without mishap under the proprietorial eye of the boatman and swung grandly into the Grand Canal, almost sideswiping an oncoming gondola.

From the relative peace of the breakfast table, the Grand Canal has a balletic quality, a picturesque and graceful parade of boats. From the helm of a boat, it resembles a carnival ghost train, with hideous things popping out at you at every turn. Huge barges loomed out of nowhere over my stern. Malevolent-looking vaporetti cleaved through the traffic to their stops, regardless of other boats. A dredger passed, almost capsizing me in its wake. A flotilla of gondolas suddenly swung across my bows, the gondoliers happily oblivious as they sang O Sole Mio to their cargo of Japanese tourists. Venetian taxis, all varnish and leather, darted back and forth at speeds that might have been appropriate on the M4, while an ambulance raced past, presumably bearing the remains of collisions downstream. Traffic in Venice was like traffic anywhere in Italy. There was no such thing as right of way. It was every boat for itself.

AFTER A series of harrowing near misses, I turned into the Rio de San Felice. Peace suddenly descended. It was a narrow side canal and I glided forward through the reflections of old stone walls, of shuttered windows, of the perfect echoing arches of bridges I passed beneath. It widened into the Canale della Misericordia, and then in a moment I was out into the lagoon. To the north, breathtaking across the flat grey waters, were the snow peaks of the Dolomites.

It was the lagoon that I wanted to explore. Some 30 miles long and almost 10 miles across at its widest point, the lagoon is Venice’s countryside, where Venetians go to escape the city. It is a wetland of marsh and mud bank, shallow waters and low islands, all a million miles from the crowds of the Rialto. Chief among the islands is Torcello, the first city in the lagoon, built long before anyone had conceived of St Mark’s Square. Ruskin called Torcello the Mother of Venice.

If navigating the canals of Venice was a tricky business, the lagoon presented its own problems. It is divided into channels, marked by thick piles on top of which sit sceptical cormorants. Under their baleful eye, the channels meet and diverge, fork and intersect, without the benefit of signposts. Take the wrong channel and you could end up in Albania.

My first stop was the cemetery island of San Michele, fairly easy to find as it lay barely 600 yards from the Fondamenta Nuove on Venice’s north side. Arrival meant parking, which I could see was going to be my biggest challenge. I was not helped by the fact that the revs on the motor seemed to be set a trifle high. There was no “dead slow” position. The lowest available speed was something closer to a marine quickstep, not at all conducive to gentle berthing at the island of the dead, especially in the wake of a funeral cortege.

I came into dock like a Patriot missile, braking dramatically at the last minute in a wash of white water by throwing the motor into reverse, and coming to a halt by grabbing a mooring ring and hanging on for dear life, my feet hooked round one of the seats. Fortunately, the funeral party was too busy grieving to take much notice of this pantomime. I tied a few nautical-looking knots and went ashore.

If there is a sweet melancholy about Venice, it overwhelms the island of San Michele. I picked up a plan of the cemetery at the gates and spent an hour or so nosing about among the departed. I found Ezra Pound’s grave, marked by a crude stone with his name, and Diaghilev’s, marked by a tomb as elaborate as one of his stage sets. Less well known is Mr Frank Stainer of Staffordshire, whose family recorded on his gravestone that he “Left Us in Peace, Febry 2nd, 1920”. Sadly, nobody is allowed to rest in peace on San Michele any more. The cemetery is almost as crowded as Venice. After 10 years they dig you up, remove the bones to an ossuary on the mainland and recycle the plot.

My knots had held and my boat was still at its mooring. I unleashed her and we headed across the lagoon. I stopped in Murano only long enough for a cappuccino. Its famous glass has made it almost as frenetic as Venice. Besides, I seemed to be moored in an area reserved for residents’ parking. A woman was shouting abuse from an upstairs window.

THE LAGOON is a mysterious place, a creature of light as much as of substance. The water is shallow and opaque, given to weird reflections, mirages, illusions. Sounds drift upon its watery acoustics without clear origin or destination. Framed by mud banks and marsh, its islands wax and wane with each tide. Many are empty, some are fishermen’s villages where the drying nets hang about small piazzas; others, such as Murano, Burano and Chioggia, support substantial towns. Here and there is evidence of grander days — an octagonal fort, an abandoned tower, a ruinous villa.

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