The Land Map before the Pub
At the beginning of the 19th Century most of the land in the immediate area of the pub was owned by the Franks family. The Franks family were a fantastically wealth Anglo-Jewish family who were prominent in the area and had Isleworth House (now called Nazareth House) as their family seat for over a century. Sir William Cooper, Chaplain-in -Ordinary to King George III married into the family and by virtue of his marriage to Lady Isabella Franks, became the owner of much of the land.
There were two other grand houses in the area, to the south of Railshead; Gordon House (which remains) and Lacy House which had many notable owners and occupiers (James Lacy, owner of the Garrick Theatre; the Honorable Sir Edward Walpole; the Earl of Warwick and the playwright Richard Brinsley Sheridan). It is Lacy House, or at least the history of its occupants, which is more significant to this story.
In 1830 or thereabouts, Lacy House was bought by Archibald Kennedy who rebuilt the house and renamed it St. Margarets House. It was because of the house and its prominence at the time that the whole area became known as St. Margarets.
Archibald Kennedy became the 1st Marquis of Ailsa, the origin we can assume, of the pub name. More about our Archie in a while.
After his death in 1846, St. Margarets House was bought and rebuilt by 'Black Jack Needham', the Earl of Kilmorey. Black Jack never lived in the house, (staying at Gordon House which he also owned) and it eventually became the Royal Naval School, a boarding school for the daughters of serving Royal Navy officers. The house later became known as Kilmorey House but was unfortunately destroyed by German bombs during the war in 1940. It was never rebuilt.
In 1853 a large area of land to the west of what is now St. Margarets Road was auctioned off as building land. A map of the plots being sold, kindly supplied by Twickenham Library shows the plots upon which The Ailsa Tavern was built (plot 1+2). The 'intended road' next to the plots became Northcote Road.
Interestingly, the notes accompanying the auction map state that "Lot 1 has a public house and lots 2, 3 and 4, 'no public house will allow to be built' [sic]".
It has not been possible to find out about the previous public house. At the time, any member of the public could apply for a license to sell beer from their house and this was likely to have been the case here. Whilst the 'beer house' may well have had a name, this did not need to be registered.
It is assumed that Lots 1 and 2 were purchased by The Isleworth Brewery Company Limited (albeit one of the companies that ended up with that name), because a couple of years later, the pub was built.