For those with a long memory from the mid 1970s to the mid 1980s a Development Land Tax was levied on landowners who disposed of development land. At its height, a 80% rate of tax was charged on gains.
This article in the FT suggests we may be about to see the return of something similar:
How Labour will try to unlock Britain’s planning system (ft.com)
The idea behind such an approach is that landowners would still receive a high enough price to incentivise sales without resorting to time-consuming and legally complex compulsory purchase orders.