Wealthy families who have tied money up in trusts have been given an extra six months to elect which of their dependants will receive the investment income.

New tax rules for existing trusts were due to take effect from April 6. These would have caught widely-used "interest in possession trusts", which allow trustees to give away income while keeping control of the capital. Under the rule change,, new trusts will be hit by inheritance tax charges every 10 years.