If I transfer part of my main residence (i.e. half the garden) to my son to build his own house will this transaction be exempt from capital gains tax? Does the answer vary if I have not actually lived in the house which was inherited from my father, but have lived in a caravan on the grounds while he was still alive and needed to rebuild the property before moving in?  

Arthur Weller replies: 

If you transfer part of the garden of your main residence to someone, this transfer should be eligible for principal private residence (PPR) relief. Even if you didn't live in the main house, but lived in a caravan on the grounds, and you 'enjoyed the use' of the grounds as part of your living in the caravan, PPR relief could be available. See HMRC’s Capital Gains internal manual.