AROUND LONDON

The statesman William Ewart Gladstone said the best way to see London was from the top of a double-decker bus. But there are other ways, too. Underground

Covering 630 square miles, the underground has 260 route-miles of track. Some parts of London south of the Thames are under-served by the ``Tube,'' but it is by far the fastest means of transport. You can take it from Heathrow Airport direct to Piccadilly Circus. One-day passes are a cheap way to criss-cross the city. The Underground is gradually getting a face-lift, and buskers (street musicians) can add variety to journeys.

Taxis

Still chunky and square and driven mostly by cheeky chappies with ``the knowledge'' - an encyclopedic memory of London streets essential to hold a license. There is a leavening of red, white, blue, and other colors among the traditional black cabs. Otherwise little has changed.

River, Canal

Thames launches travel from Westminster pier to Greenwich, the Tower of London, and elsewhere, usually with multilingual commentaries. There is now a river bus service from Charing Cross to the new City airport in the East End, from where you can fly to Paris, Brussels, and other European centers.

Shanks' Pony

If you lack the nerve to stroll alone, there are daily guided walks through Dickensian London, architectural London, artistic London, lawyers' London, even murderous London.

Best source of information: London Tourist Board and Convention Centre, Victoria Station.

Best recent guide: Michael Leapman's ``Book of London'' (London: Weidenfeld and Nicolson, 1989). Comprehensive, well-written and illustrated, and at 18 (about $30), worth the money.