Swapping assets - tax implications?

[BNmum]

DH and DBIL would like to swap assets (house for land), is this possible and what are the tax implications?

The assets would be of the same monetary value and no money would exchange hands. Could they 'gift' it to each other?

They can gift it to each other, however, if one of them dies within 7 years and the asset + value of their estate is over the IHT allowance then the gift comes back into the estate and IHT is payable, the amount of tax due does reduce over the 7 years though.