Nil Rate Band Discretionary Trust: Understanding Older Wills

Why NRBDTs were used

Before October 2007, the inheritance tax nil rate band (NRB — the amount that could pass free of IHT) was not transferable between spouses. Each person had their own NRB (£312,000 in 2007), but if a spouse left their entire estate to the survivor on the first death, the first NRB was wasted — the surviving spouse would then die with a doubled estate but only one NRB.

The solution was the NRBDT. Instead of leaving everything to the surviving spouse, the will created a discretionary trust of up to the NRB value on the first death. The surviving spouse would not be the sole beneficiary of the full estate — some of it went into the trust — preserving the first NRB. The surviving spouse could still benefit from the trust at the trustees' discretion.

The transferable NRB changed everything

In October 2007, the Finance Act 2008 introduced the transferable nil rate band. This allows the unused NRB of the first spouse to die to be transferred to the surviving spouse's estate. In effect, a surviving spouse can now have a combined NRB of up to £650,000 (£325,000 × 2) without any need for a trust structure.

This makes NRBDTs largely redundant for IHT planning purposes. A will that was made in 2003 and contains an NRBDT was entirely sensible tax planning at the time — but the same will administered today may create unnecessary complexity without a corresponding tax benefit.

The NRBDT's practical effect on the estate

When administering an estate with an NRBDT, the executor will typically face:

• A discretionary trust holding assets up to the NRB value (currently £325,000) on behalf of a class of beneficiaries that includes the surviving spouse, children, and grandchildren
• A requirement to appoint trustees (who may be the same as the executors) to manage the trust fund
• Ongoing trust administration — trustee investments, SA900 tax returns, and annual account keeping — unless the trust is wound up

This is time-consuming and costly if the trust's only original purpose was IHT saving that the transferable NRB has now made unnecessary.

Winding up the NRBDT

The trustees can wind up the NRBDT and distribute the assets to the surviving spouse (or other beneficiaries) at any time, using a deed of appointment. This is often the most practical course of action.

If the distribution is made within 2 years of the date of death, section 144 of the Inheritance Tax Act 1984 may apply. Under s.144, a distribution from a discretionary will trust within 2 years of death is read back into the will for IHT purposes — as if the deceased had made the distribution directly. This can change the IHT position.

After 2 years, the trust is simply wound up in the normal way for a discretionary trust. Any assets appointed to the surviving spouse are not subject to the 10-yearly periodic charge (because the trust is being wound up, not continuing).

NRBDT loan arrangements

Many NRBDTs were funded not by actually segregating assets but by a loan arrangement. The surviving spouse would borrow the NRB value from the trust (often secured by a charge on the family home), and the trust held the debt as its asset. This created an artificial deduction in the surviving spouse's estate.

HMRC now takes a sceptical view of certain NRBDT loan arrangements, particularly those involving "double dips" (using the NRB twice in a way that was not intended by the legislation). If an NRBDT loan arrangement is in place, take specialist advice before administering the estate.

Practical advice for executors

1. Read the will carefully to establish whether an NRBDT is created and what its terms are
2. Calculate whether the trust actually provides an IHT benefit, given the transferable NRB
3. Consider whether to wind up the trust early (within 2 years of death is most flexible)
4. Seek solicitor advice — NRBDTs involve specialist trust and IHT knowledge
5. Check whether a loan arrangement is in place and what the outstanding loan balance is

For more on IHT planning tools, see our inheritance tax UK 2026–27 guide, the life interest trust (IPDI) guide, and our deed of variation guide. For general probate guidance, see the complete UK probate guide 2026, estate administration checklist, and IHT400 guide. For annual trust tax returns, see the SA900 trust tax return guide. For applying for probate, see our applying for probate guide. For the executor's first steps, see our executor first steps guide. For bare trusts for minor beneficiaries, see our bare trust for minor beneficiaries guide. Farra can help — get started here.