Historically 99 years was the longest term for leases in English laws. I don't think that's incorporated in laws any more, but it has just continued as common practice.
You may be right historically, but I don't think it's common practice any more - there are quite a few "virtual freehold" leases of 999 years, and most other domestic leaseholds are 125+ years when they start. When a leashold goes below 90 years its value dips sharply.
Historically 99 years was the longest term for leases in English laws. I don't think that's incorporated in laws any more, but it has just continued as common practice.
You may be right historically, but I don't think it's common practice any more - there are quite a few "virtual freehold" leases of 999 years, and most other domestic leaseholds are 125+ years when they start. When a leashold goes below 90 years its value dips sharply.
999 years is considered a "permanent" lease [1]. 99 years is considered a "more than a lifetime lease" [2]
[1] https://en.wikipedia.org/wiki/999-year_lease [2] https://en.wikipedia.org/wiki/99-year_lease
So they can renegotiate the terms of the leasing in a reasonable time span?