Unbundling interests in land

[Extract] It used to be that 'a man's house is his castle' and indeed this aphorism is reflected in the common law doctrine of cuius est solum, eius est usque ad coelum et ad inferos or he who owns the soil is theirs up to heaven and down to hell. Increasingly however this doctrine has been narrowed as interests in land have become unbundled. I draw a distinction here between the recognition that one cannot literally own 'up to heaven' or 'down to hell' and what is considered to constitute 'land'