Rumours leaked from government sources indicate that the current relief from IHT for business assets may be restricted so that it is only available provided the asset isn’t sold immediately post death. 
As it currently stands, business relief excludes business assets from IHT when it is passed onto family members; this was designed to allow business owners to pass their business down the generations without hefty tax bills forcing the foreclosure of the business. However the policy isn’t quite working as intended, with many beneficiaries selling the family business immediately post death.
Business relief is only available if the deceased owned the business/asset for at least 2 years before they passed away. Business relief isn’t available on an asset that also qualifies for agricultural relief and you can’t claim business relief on an asset that isn’t needed for future use in the business eg)
If you use one room in a building as a shop and the other rooms are used as your home, the shop will qualify for Business Relief but the rooms won’t.