CREDITS AN AMERICAN WEREWOLF IN LONDON, 1981 dir: John Landis David Naughton Griffin Dunne Jenny Agutter Griffin Dunne Alan Ford

A pub full of character actors rhubarbing away on the 'Yorkshire Moors' can only mean bad news for two American backpackers.

The moors were filmed around the Black Mountains in Wales, and 'East Proctor' is in reality the tiny village of Crickadarn, about six miles southeast of Builth Wells off the A479.

If you want to join the locals here for a pint at 'The Slaughtered Lamb', youíll have quite a journey. Although the exterior is an empty cottage dressed up for the movie, the interior, where Lila Kaye tends bar and a frighteningly young Rik Mayall plays chess, is in Surrey.

Itís The Black Swan, Old Lane at the junction with Ockham Lane, Martyrís Green, about a mile northwest of Effingham Junction between Guildford and Leatherhead. This photogenic pub has also been featured in TV’s Inspector Morse.

The 'Slaughtered Lamb' interior: The Black Swan, Martyr's Green, Surrey

The hospital in which David Kessler (David Naughton) recovers from a nasty wolf bite was the Princess Beatrice Maternity Hospital on Finborough Road at Lillie Road in Earlís Court, London SW5. The building is still there, and is now a hostel for the homeless. Around the corner at 64 Coleherne Road, SW10, you can see the flat of nurse Alex Price (Jenny Agutter), where David does some shape-shifting to ëBad Moon Risingí (tube: Earlís Court).

Unusually, the tube station, where the city gent gets chomped, was filmed, during the wee small hours, at Tottenham Court Road Station (London Transport’s all-purpose location, the closed Aldwych Station in the Strand, is almost invariably used for filming).

The undead victims pop up in a studio recreation of the old Eros News Cinema (now GAP clothes store) on the corner of Shaftesbury Avenue in Piccadilly Circus. And once again John Landis demonstrates his talent for staging major set-pieces in impossible locations by setting the climactic mayhem smack in the middle of Piccadilly Circus itself, although, if you look carefully, you can see a wobbly street sign.

In fact, some of this sequence was filmed on a mock-up of the Circus at Twickenham Studios.

The dark alley, where the wolf is finally cornered, which seems to be in the West End, is Winchester Walk, off the familiar location of Park Street in Borough (tube: London Bridge).

The dull and belated sequel, An American Werewolf in Paris, was filmed largely in Luxembourg.