Inspired by Why are leases made for 99-year terms?, which mentions medieval leases of 1000 and 999 years. Are any of these still extant and binding, or have subsequent events (legal revision, revolutions, etc.) made them all null and void? I doubt any have expired yet at least in Britain since 1066 is pretty much how far back any legal title there goes. But sometime in the next few centuries could John Smith cite a record in the Domesday book and demand his land back that’s now part of central London?
I’m not sure about 999 year leases but I’ve certainly seen advertisements in the London financial press offering 125 year leases. The ones I recall were being offered by the Grosvenor Estates.
What length lease does the US Embassy have on its site in Grosvenor Square?
A quick Google search for “999-year lease” makes it look to me that they are still being made in the UK and seem to not be uncommon. Someone who is familiar with British real estate laws (and I’m sure one will be along any minute now) will have to provide more info.