OBSERVATION DECK: LONDON

Find cheap flights on Brussels Airlines

Not all those who wander are lost, JRR Tolkien once said, his maxim now advertising a wonderful exhibition of writing about landscapes at the British Library. But sometimes those who wander are - and happily, deliberately so.

This has always been my preferred way to explore London since I first came here to live, two years ago. And it is the most serendipitous way to discover a place, perhaps in the same way as the 19th-century French flaneur, a person happy just to wander idly - an urban explorer. I would pick an area of the city with a Tube stop, jump off and just start walking in any direction that looked like it might yield some interesting sights and sounds.

There is something exhilarating and freeing about being lost, the idea that around the next corner you could come across a lucky find, whether it's a classic London pub, a canal-side walk, a beautiful Georgian square or a lively street market. Just the act of discovery, of acquainting yourself with some unknown place and being pleasantly surprised can create an indelible memory.

Some of my favourite discoveries made on random wanderings include a statue of a boy and a dolphin between Tower Bridge and St Katharine Docks; the rose gardens in Regent's Park; Brixton Market; a restaurant fashioned from an old pump room (complete with all the original machinery) in Wapping; the pelicans in St James's Park; a beautifully restored church in the middle of gay Soho; Columbia Road flower market; Albert Bridge; a rooftop cinema in Shoreditch; and an old (still-functioning) music hall in Shadwell on the banks of the Thames.

But my favourite place of all was barred to me the first time I came across it. Through the rusting bars of a solid, old-fashioned gate I glimpsed, tantalisingly out of reach, a beautiful garden of mature trees, neat lawns and meandering pathways. Huge walls shielded it from the street and stretched down to a busy main road by the river. Here, in the middle of this big, noisy, high-octane city, was a magical secret garden. The gate was locked and I was surprised how disappointed I felt. "Chelsea Physic Garden" read the sign.

Right now London is clearly having a moment: last month the Queen's Diamond Jubilee had thousands thronging the streets, jamming the Mall, standing ten deep by the Thames in the rain. The month before, Chelsea FC won the Champions League, and this month 10 million visitors will descend on the city for the 2012 Olympic Games. Add to that the cultural Olympiad and more festivals than you can shake a pair of wellies at, and London will be jumping - a riot of colour, spectacle and celebration. Things may get a little busy.

So amid the noise and haste, if you seek a little bit of serenity to restore your sanity, head to Chelsea's Physic Garden, as I did. Founded in 1673 by the Society of Apothecaries of London so that their apprentices could grow and study medicinal plants, these four lush acres stand among the elegant town houses of Chelsea, just a stone's throw from the King's Road. These days you will find a vegetable garden, an inviting cafe, mossy pathways, fruit trees, exotic foreign plants under glass, wildflowers, a herb garden and a colony of beehives in a far corner.

Take a wander through the medicinal plants, breathe in the lavender, watch bees drunk on nectar weave and buzz from bloom to bloom, and marvel that this soothing balm of a place exists adjacent to one of London's busiest shopping streets. And, as if by magic, the sound of the traffic will fade, the smell of herbs and flowers will fill the air and even the rain falling - and it surely will, even in July - won't bother you. Later, if you check the new Oxford dictionary for the definition of physic, you will find it means 'the art of healing'.

Next month: Hamburg

Find cheap flights on Brussels Airlines