If you have children from a previous relationship and are now married or living with a new partner, your estate plan needs to do two things at once: look after the surviving spouse, and make sure your own children are not unintentionally cut out of their inheritance. Standard wills and the default intestacy rules were not built for this, which is why blended families account for a disproportionate share of contested estates in the UK courts.
This guide explains how inheritance tax (IHT) actually works for a blended family in 2026, the specific tools used to protect both sides of the household, and the practical steps to take before HMRC’s frozen thresholds quietly pull more of your estate into the 40% bracket.
Quick eligibility check: If you and your spouse together own assets worth more than £650,000 (or more than £1 million including a family home), and either of you has children from a previous relationship, you are likely to need a tailored plan rather than off-the-shelf mirror wills. Speak to our IHT Experts for a confidential review.
Key Takeaways
- The 2026/27 nil-rate band remains £325,000 per person and the residence nil-rate band remains £175,000. A married couple can pass up to £1 million tax-free where a qualifying home goes to direct descendants.
- HMRC treats stepchildren, adopted children and foster children as direct descendants for the residence nil-rate band, so blended families do not lose this allowance simply because some beneficiaries are not biological children.
- Stepchildren do not inherit automatically under the rules of intestacy in England and Wales. Without a will that names them, they receive nothing.
- Life interest trusts, discretionary trusts, severance of joint tenancy and life insurance written into trust are the four most common tools used to balance a surviving spouse’s needs with the inheritance of children from a previous relationship.
- The Autumn 2025 Budget extended the freeze on IHT thresholds to April 2031, so more blended family estates will fall into the IHT net every year that property values rise.
Why Blended Families Need a Different Approach
A first-marriage estate plan usually has one job: pass everything to the surviving spouse, then to the shared children. A blended family estate plan has at least three competing priorities running through it at the same time:
- The surviving spouse needs somewhere to live and enough income to do so.
- Children from the first relationship expect to inherit from their parent, not from a stepparent who may later remarry.
- Any shared children of the new relationship need to be treated consistently with the others.
When these are not addressed in writing, the default rules take over. Under the rules of intestacy in England and Wales, a stepchild has no automatic right to inherit. The estate passes to the surviving spouse first, then to the deceased’s biological children, and a child raised in the household for twenty years can find themselves with no entitlement at all. Even where a will exists, a structure that leaves everything to the surviving spouse outright leaves them free to direct the estate elsewhere later, including to a future partner or their own bloodline.
The good news is that all of this is solvable with the right combination of will, trust structure and ownership arrangement. The rest of this guide walks through each option.
Inheritance Tax Rules That Apply to Your Estate in 2026
Before choosing a structure, it helps to know exactly what HMRC will look at. Inheritance tax is charged at 40% on the portion of an estate above the available allowances. There are two main allowances and one important taper.
Nil-rate band (NRB): £325,000 per person for 2026/27. Frozen at this figure since 2009 and now extended to April 2031 following the Autumn 2025 Budget.
Residence nil-rate band (RNRB): £175,000 per person where a qualifying main residence passes to direct descendants. For RNRB purposes, HMRC’s definition of direct descendant includes children, grandchildren, stepchildren, adopted children and foster children, as well as the spouses and civil partners (and surviving widows or widowers, where they have not since remarried) of those descendants.
Spouse exemption: Anything left to a UK-resident spouse or civil partner passes free of IHT, with no upper limit. Any unused NRB or RNRB from the first death can be transferred to the surviving spouse and claimed on the second death.
The £2 million taper: Where the total estate is worth more than £2 million, the RNRB reduces by £1 for every £2 above that figure. It disappears entirely at £2.35 million for an individual, or £2.7 million for a surviving spouse with the full transferred allowance. For blended families with London property, this taper is the single most common reason families lose six-figure allowances without realising it.
Worth knowing: From April 2027, unused pension funds will be brought into the IHT estate following the Autumn 2024 Budget announcement. Blended families who rely on pension nominations to provide for stepchildren should review those nominations now.
Book a fixed-fee IHT review if your combined estate is above £1.5 million and includes property, pensions or business interests.
Common Blended Family Scenarios (And What Usually Goes Wrong)
These are the five situations we see most often. If any of them describes you, the standard mirror will is unlikely to be enough.
Scenario 1: One spouse owns the family home outright. The owner wants their partner to live there for life, and their own children to inherit eventually. A simple will leaving the house to the spouse means the children may never see it.
Scenario 2: The couple owns the home as joint tenants. On the first death, the home passes automatically to the survivor regardless of what the will says. Neither set of children inherits a share.
Scenario 3: One side of the family is significantly wealthier than the other. Without ringfencing, the wealthier side’s assets can flow to the other side’s children if the survivor dies later without an updated will.
Scenario 4: A second marriage with shared children plus children from previous relationships. Three groups of beneficiaries with different relationships to each parent. Mirror wills are rarely the right answer here on their own.
Scenario 5: An estate worth more than £2 million. RNRB tapering kicks in, and lifetime planning becomes more important than will structure on its own.
The Four Tools That Solve Most Blended Family Problems
1. Life Interest Trust Over the Family Home
A life interest trust (sometimes called an immediate post-death interest trust, or IPDI) gives the surviving spouse the right to live in the family home and receive any income from trust assets for the rest of their life. When they die, the underlying capital passes to the named beneficiaries, usually the children from the first marriage, under the terms of the original trust rather than under the surviving spouse’s own will.
This is the single most widely used structure in blended family planning. It gives the surviving spouse complete security of housing and prevents the inheritance from being redirected if the survivor later remarries, falls out with their stepchildren, or simply changes their mind. From an IHT point of view, the trust assets are treated as belonging to the surviving spouse for the second death calculation, so the spouse exemption on the first death is preserved and the RNRB can still be claimed on the home.
2. Discretionary Trust for Flexibility
A discretionary trust is used where family circumstances are likely to change, or where one or more beneficiaries may need protection (for example, a child going through a divorce, a family member with a means-tested benefits claim, or grandchildren not yet born). The trustees decide how and when to make distributions among the named class of beneficiaries.
Discretionary trusts work well as the named recipient of a life insurance payout. The proceeds sit outside the estate for IHT purposes and the trustees control how the money is used, which is useful when there are several different sets of children to provide for. There are specific tax rules that apply to discretionary trusts holding more than the nil-rate band (notably ten-year anniversary charges and exit charges), so this structure should be set up with proper advice.
3. Tenants in Common Instead of Joint Tenants
How you and your partner own your home matters as much as what your will says. Under joint tenancy, the home passes automatically to the survivor and your share cannot be left to your own children. Under tenants in common, each owner holds a defined share that they are free to leave to whoever they choose, usually into a life interest trust for the survivor with the children as eventual beneficiaries.
Switching from joint tenancy to tenants in common is called severing the joint tenancy. It is a straightforward legal step, completed with a notice to the other owner and a Form SEV restriction at the Land Registry, and is often the first practical change a blended family makes when reviewing their estate plan.
4. Life Insurance Written Into Trust
Life insurance is the part of the plan that most blended families overlook. A whole-of-life policy written into trust pays out on death, sits outside the estate for IHT purposes, and reaches the beneficiaries within weeks rather than waiting for probate.
Two uses are common. The first is to fund the IHT bill itself, which becomes due six months after the end of the month of death and often forces a sale of the family home. The second is to provide a separate, ringfenced inheritance for children from a first marriage, leaving other estate assets free to support the surviving spouse. Premiums need to be sustainable for the long term, so this is a conversation to have with both a financial adviser and a tax adviser before any policy is taken out.
Not sure which combination fits your family? Most blended families use two or three of these tools together. We work through the right mix as part of our IHT planning service
Mirror Wills: When They Work and When They Do Not
Mirror wills are two near-identical wills made by spouses or partners. They leave the estate first to each other, then to a shared list of beneficiaries. They are quick, cost-effective, and well-suited to first marriages with shared children.
For a blended family, the limitations are important to understand. A mirror will is not legally binding on the surviving spouse. Once the first partner dies, the survivor is free to change their will, remarry, or leave the estate to a different set of beneficiaries entirely. (In England and Wales, marriage automatically revokes an existing will unless the will was made in contemplation of that marriage; the position in Scotland is different.)
Where a blended family does use mirror wills, they are usually combined with a life interest trust over the family home and a clear conversation with the adult children about what is in place. The trust does the protective work that the mirror will alone cannot.
How Lifetime Gifting Fits In
For estates above the available allowances, lifetime gifting can bring the IHT exposure down significantly. The headline rules:
- Gifts to a UK-resident spouse or civil partner are exempt from IHT, with no limit.
- Each individual has a £3,000 annual gift exemption that can be carried forward one tax year.
- Small gifts of up to £250 per recipient per tax year are exempt.
- Gifts out of surplus income are exempt where they form a regular pattern and do not affect the donor’s standard of living.
- Larger gifts to individuals (potentially exempt transfers, or PETs) fall outside the estate if the donor survives seven years from the date of the gift.
For blended families, gifting can be used to provide for children from a first marriage during the parent’s lifetime, reducing pressure on the post-death distribution and lowering the chance of disputes between stepchildren and a surviving spouse. The seven-year clock and record-keeping requirements make this an area where written advice is worthwhile.
Talking to the Family
The legal structures matter, but the conversation with the family matters too. In our experience, the disputes that end up in court rarely begin as a fight about money. They begin with surprised beneficiaries who had no idea what was in the will.
A short family meeting, ideally before the plan is finalised, gives everyone the chance to understand what has been put in place and why. Families do not have to share the numbers, but explaining the structure (who lives where, who eventually inherits the home, how a life policy works) tends to reduce friction later on.
When to Get Professional Advice
Blended family estate planning sits at the meeting point of three specialisms: wills and probate, trusts, and inheritance tax planning. Most families benefit from input from all three.
- A solicitor drafts the wills, the trust deeds and the property documents.
- A tax adviser models the IHT position under different scenarios, identifies which allowances apply, and reviews the position after every Budget.
- A financial adviser handles life insurance, pension nominations and any investments held in trust.
Plans should be reviewed every three to five years, and immediately after any of the following: a marriage or divorce, the birth of a child or grandchild, a house move, the sale or purchase of a business, or a change in tax law. Three changes coming through right now make 2026 a particularly good year for a review: the freeze on IHT thresholds extended to 2031, the cap on agricultural and business property relief from April 2026, and the inclusion of unused pensions in the IHT estate from April 2027.
Frequently Asked Questions
Do stepchildren count as direct descendants for the residence nil-rate band?
Yes. HMRC’s IHT435 claim form confirms that stepchildren, adopted children and foster children are treated as direct descendants. The £175,000 RNRB is available where a qualifying home passes to any of them.
Do stepchildren inherit automatically if there is no will?
No. Under the rules of intestacy in England and Wales, stepchildren have no automatic entitlement unless they were legally adopted. A will that names them is essential.
What is the IHT allowance for a married couple in 2026?
Up to £1 million combined, made up of two £325,000 nil-rate bands plus two £175,000 residence nil-rate bands, where a qualifying home passes to direct descendants. The RNRB is reduced where the estate is worth more than £2 million and is fully withdrawn at £2.7 million for a surviving spouse.
Can the surviving spouse change a mirror will?
Yes. A mirror will is not legally binding on the survivor. This is the main reason blended families use a life interest trust over the home rather than relying on mirror wills alone.
How long does it take to put a blended family estate plan in place?
A typical plan involving wills, severance of joint tenancy, a life interest trust and a life policy review takes around four to six weeks from the first meeting to signed documents.
Take the Next Step
Blended family estate plans reward early action. Property values are rising, the IHT thresholds are frozen until 2031, and the rules on pensions and business reliefs are tightening. The earlier the structure is in place, the more allowances and reliefs the estate can claim.
Our team works with blended family clients across London and the rest of the UK to put together estate plans that protect both the surviving spouse and the children of the first relationship. We work alongside your solicitor and financial adviser, or we can introduce you to ours.
To arrange a confidential, no-obligation initial call, fill in the form on our contact page