Part of our Best Pubs in London microsite. Is your local listed?
Technically, the Ailsa is in St Margaret's, but as few non-locals are aware of that place name, the pub markets itself as being in Twickenham. Which it kind of is, if you squint, but possibly also Richmond or Isleworth.
Its out-of-the-way location means it inevitably attracts a mostly local crowd, drawn from the many fine avenues and drives in this well-to-do part of town. Quite a few rugby fans pile in on a match day, too, though the stadium is a bit of a trek from here.

The pub's unique name is said to be that of a former landlady. According to local legend, a secret passage ran from the pub to the home of a local dignitary, to better enable assignations. More likely, it was named after the dignitary... the Marquis of Ailsa lived (and died) in St Margaret's in the 1840s.
This is a lovely, friendly pub, with stone floors and wooden beams a-go-go. It has a real community focus, with a pub quiz, and regular poker nights, with players crowding round the back tables. Beer is by Shepherd Neame, with the usual tipples on offer. The food includes a bunch of pub classics and a small pizza menu.

Naturally, for such a leafy area, the pub also boasts a sizeable beer garden, with plenty of covered tables.

The pub sits almost opposite one of west London's great curiosities. The Kilmorey Mausoleum is a magnificent Victorian tomb, which followed its eventual co-occupant the Earl of Kilmorey from Brompton to Weybridge and eventually St Margaret's. It's locked away behind a high wall, but you can catch a glimpse through a crack in the gate. The garden really was accessible by tunnel from the Earl's house, which perhaps got conflated with the supposed Ailsa tunnel over the years.