Inheritance Tax and Step Children UK: RNRB, Intestacy, and Blended Family Will Planning (2026)
Step-children ARE direct descendants for the RNRB (s8K(3) IHTA 1984) — but they get NOTHING if the step-parent dies without a will. Intestacy completely excludes step-children. A will naming step-children is essential for any blended family, and IPDI trust planning can preserve the £175,000 RNRB while protecting the surviving spouse.
| Scenario | RNRB Available? | Intestacy Right? | Will Required? | Notes |
|---|---|---|---|---|
| Step-child inherits home directly under the will | YES — home passes to direct descendant (step-child) | NO — step-children do not inherit on intestacy | YES — must specify in will | Simplest: will leaves home to step-child; RNRB (£175k) fully applies; step-child pays no IHT above threshold |
| Home passes to IPDI trust; step-children are remaindermen | PRESERVED — s8H IHTA 1984 on IPDI termination | NO | YES — IPDI trust must be in the will | Surviving spouse is life tenant; step-children get capital on survivor's death; RNRB preserved |
| Home passes to discretionary trust (step-children are only beneficiaries) | LOST — discretionary trust breaks RNRB even if only step-children benefit | NO | YES — but wrong trust type | Up to £70k extra IHT vs IPDI; update any pre-2017 NRB discretionary trust wills |
| Step-parent dies without a will (intestacy) | N/A — intestacy may direct home to surviving spouse or biological children; step-children get nothing | NOTHING for step-children under Administration of Estates Act 1925 | CRITICAL — no will = step-children excluded | Step-children receive no automatic inheritance on step-parent's intestacy; biological children inherit |
| Child of a former spouse (post-divorce) | YES — former spouse's child is still a step-child under s8K(3) IHTA | NO — do not inherit on intestacy regardless | YES | Post-divorce: the child of an ex-spouse IS still a step-child for RNRB; must be in the will to inherit |
| Adopted step-child | YES — adopted children are direct descendants under s8K(3)(b) IHTA | YES — adopted children DO inherit on intestacy as if biological | Optional (protected by intestacy), but recommended | Adoption creates full legal parent-child relationship; adopted step-child inherits on intestacy |
| Foster child (fostered by deceased while under 18) | YES — s8K(3)(d) IHTA — foster child qualifies if fostered while under 18 by the deceased | NO — foster children do not inherit on intestacy | YES — must be named in will | Foster child RNRB qualification added by Finance Act 2018; must have been fostered by the deceased personally |
RNRB: s8D IHTA 1984 — £175,000 (frozen to 2030). Direct descendants: s8K IHTA 1984 — biological children; adopted children (s8K(3)(b)); step-children = child of current/FORMER spouse/CP (s8K(3)(c)); foster children fostered while under 18 by the deceased (s8K(3)(d) — Finance Act 2018). RNRB on IPDI termination: s8H IHTA 1984. Discretionary trust: RNRB LOST. Intestacy: Administration of Estates Act 1925 — surviving spouse (statutory legacy + shared residue); biological/adopted children; step-children = EXCLUDED. Divorce: step-child status unchanged (s8K(3) — 'former' spouse/CP); ex-spouse's appointment in will revoked by s18A Wills Act 1837 — step-child bequest survives. Adopted step-child: full legal child (Adoption Act 1976; ACA 2002) — inherits on intestacy. Parental responsibility for step-children: s4A Children Act 1989 (by agreement or order). Guardian appointment in will: s5 Children Act 1989 — requires parental responsibility. IHT married couples allowance: s18 IHTA 1984 spousal exemption applies on gifts to spouse; step-child is NOT the spouse.
Step Children and Inheritance Tax: Complete Guide
Are step-children direct descendants for RNRB purposes?
Yes — step-children are explicitly included in the definition of 'direct descendants' for RNRB purposes under s8K(3) IHTA 1984. The IHTA defines a 'direct descendant' as including: a child of the deceased (biological, adopted, or fostered); a step-child (meaning a child of the deceased's spouse or civil partner, whether current or former); and the lineal descendants of any of the above (grandchildren, great-grandchildren, etc.). The step-child definition covers: children of a current spouse or civil partner; children of a former spouse or civil partner (even after divorce or dissolution). So if a woman has a step-daughter — the biological daughter of her husband (whether current or divorced) — and the woman leaves her home to the step-daughter in her will, the RNRB (up to £175,000 in 2026/27) applies to the value of the home. The practical implication: a step-parent who wants to ensure the RNRB applies to their estate when leaving the home to step-children must: (1) make a valid will leaving the home to the step-children (or via an IPDI trust with step-children as remaindermen); and (2) NOT use a discretionary trust for the home (even if the step-children are the only discretionary beneficiaries, the RNRB is lost on a discretionary trust).
The intestacy trap — step-children receive nothing without a will
This is the most critical and commonly overlooked risk for blended families: under the English intestacy rules (Administration of Estates Act 1925, as amended), step-children have NO automatic right to inherit from a step-parent on intestacy. The intestacy rules provide for: the surviving spouse or civil partner (statutory legacy + share of residue); biological children (or their children, if predeceased); adopted children (treated as biological children); but NOT step-children. A typical blended family scenario: man has two children from a previous marriage (his biological children); he remarries; his new wife has two children from her previous marriage (his step-children). He dies without a will. Under intestacy: everything goes to his new wife (the surviving spouse) — if the estate is small — or the statutory legacy plus shared residue to his new wife AND his biological children. His step-children receive NOTHING. His new wife's children (his step-children) are not his legal heirs. If his new wife subsequently dies without a will: everything then passes to HER biological children (including the step-children of the man). So the man's biological children may end up with nothing. For blended families: separate wills for each spouse are essential; each spouse must specifically provide for the other's children; mirror wills (identical wills for each spouse) may not be appropriate where children from different relationships are involved — a family will trust structure (IPDI or mutual wills) may be better.
How to ensure step-children inherit — will planning for blended families
For a step-parent to provide for step-children, the will must explicitly name them. Options for leaving the home and estate to step-children: (1) Direct bequest in will: leave the home directly to the step-children (or a percentage share to each). RNRB applies on the value passing to step-children. Clear and simple but: the surviving spouse loses the right to live in the home if the step-children inherit. (2) IPDI trust: leave the home to an IPDI trust for the surviving spouse (who is also the biological parent of the step-children); on the surviving spouse's death, the home passes to the step-children as remaindermen. RNRB is preserved (s8H IHTA 1984). Benefit: surviving spouse is protected; step-children get the capital on the survivor's death. Risk: if the surviving biological parent (the step-children's own parent) leaves their estate to different beneficiaries on the second death, the step-parent's IPDI trust protects the step-children's share. (3) Protective wills for both spouses: each spouse makes a will providing for the other's children — ideally reviewed together. (4) Mutual wills: legally binding agreement that neither spouse will revoke their will without the other's consent; technically complex; usually avoided in favour of IPDI trusts. (5) Life insurance: a policy written in trust for the step-children (named as beneficiaries) provides for them outside the estate, avoiding probate delays and IHT.
Divorce and step-children — what changes
What happens to the step-child relationship for IHT purposes when the couple divorces: RNRB: a step-child's status does NOT change on divorce. Section 8K(3) IHTA 1984 defines a step-child as the child of a person's spouse or civil partner, 'or former spouse or civil partner'. The 'former' is explicit — a child of an ex-spouse (post-divorce) remains a step-child for RNRB purposes. So a man who divorces his wife but continues to have a close relationship with his step-daughter (his ex-wife's daughter): if he leaves the home to the step-daughter in his will, the RNRB applies. Intestacy: divorce DOES affect intestacy rights for the former spouse (a former spouse ceases to be the surviving spouse for intestacy purposes on divorce). But the former spouse's children (the step-children) are still NOT included in the man's intestacy — they never were. The divorce changes nothing for the step-children's position on intestacy. Will: if the man made a will before the divorce naming his step-daughter, divorce does NOT revoke the will in England and Wales (unlike marriage, which revokes a will under s18 Wills Act 1837). However, it DOES revoke any appointment of the former spouse as executor or beneficiary (s18A Wills Act 1837). So post-divorce: the step-daughter bequest SURVIVES if she was named directly; the ex-wife's appointment as executor does NOT survive. A will review after divorce is strongly recommended.
Guardianship for step-children — a separate but critical planning point
Inheritance planning for step-children is closely linked to guardianship planning for minor step-children. A step-parent who has cared for step-children as their own may want to appoint a guardian in the event of their death. Guardian appointment: s5 Children Act 1989 allows a person with parental responsibility to appoint a guardian for their child in a will. Step-parents do not automatically have parental responsibility (unless they adopted the step-child, or the court made a specific order). However, a step-parent with a Special Guardianship Order (SGO) or parental responsibility can appoint a guardian in their will. Parental responsibility for step-children: a step-parent can acquire parental responsibility by: adoption (complete legal parenthood); a Parental Responsibility Agreement or Order (s4A Children Act 1989 — with consent of the biological parent who also has parental responsibility); or a Child Arrangements Order. Without parental responsibility: the step-parent cannot appoint a guardian; care of the minor step-children defaults to the surviving biological parent. For blended families: the will should address: (1) financial inheritance for step-children; (2) guardianship if the step-parent has parental responsibility; (3) trustees for any trust holding assets for minor step-children; and (4) letter of wishes explaining the testator's intentions if a discretionary trust is used.
Frequently Asked Questions
Do step-children qualify for the RNRB (Residence Nil Rate Band)?
Yes — step-children are direct descendants for RNRB purposes under s8K(3) IHTA 1984. A step-child is defined as a child of the deceased's current or former spouse or civil partner. If a step-parent leaves the family home to their step-child (or via an IPDI trust with the step-child as remainderman), the RNRB (£175,000 for 2026/27) applies to the value of the home. RNRB is LOST if the home passes to a discretionary trust, even if the step-children are the only beneficiaries. The step-parent must make a will — step-children receive nothing on intestacy under the Administration of Estates Act 1925.
Do step-children inherit if there is no will?
No — step-children have NO automatic right to inherit from a step-parent under the intestacy rules (Administration of Estates Act 1925). On intestacy, the estate passes to the surviving spouse and/or biological and adopted children. Step-children are entirely excluded. A step-parent who wants to provide for step-children MUST make a will naming them explicitly. This is one of the most common and serious planning failures for blended families. Without a will, the step-children receive nothing regardless of the closeness of their relationship with the step-parent.
Does the RNRB apply to a child of a former spouse (post-divorce)?
Yes — the definition of 'step-child' in s8K(3) IHTA 1984 explicitly includes a child of a 'former' spouse or civil partner. The word 'former' is included in the statute, so a child of an ex-spouse (after divorce) remains a step-child for RNRB purposes. If a man divorced his wife but maintained a relationship with her child, he can leave his home to the step-child in his will and the RNRB will apply. Note: if the step-parent's will was made before the divorce, the bequest to the step-child (the ex-spouse's child) SURVIVES divorce — only bequests to and appointments of the former SPOUSE are affected by s18A Wills Act 1837. The step-child's inheritance is unaffected by the divorce.
Do foster children qualify for the RNRB?
Yes — foster children are direct descendants for RNRB purposes under s8K(3)(d) IHTA 1984 (as inserted by Finance Act 2018). The qualification: the child must have been fostered or cared for by the deceased while under the age of 18. It is the PERSONAL caring relationship that matters — not all foster children in general, only those fostered by the deceased individually. If the deceased fostered a child under 18 and later leaves their home to that child in a will, the RNRB applies to the value of the home. Foster children do NOT inherit on intestacy (same as step-children) — they must be named in a will.
How should a step-parent structure their will to protect step-children?
For a step-parent in a blended family: (1) Make a will naming the step-children explicitly (they receive nothing on intestacy); (2) To protect the surviving spouse AND the step-children simultaneously, use an IPDI trust in the will — the surviving spouse has a life interest (right to income and/or occupation); on the survivor's death, the home passes to the step-children as remaindermen; RNRB preserved under s8H IHTA; (3) Avoid a discretionary trust for the home — the RNRB is LOST; (4) If the step-parent also has biological children, separate trusts (or specific shares) should provide for each set of children; (5) Consider life insurance written in trust for the step-children to provide for them outside the estate immediately on the step-parent's death; (6) Review guardianship provisions if the step-children are under 18 and the step-parent has parental responsibility.
Without a Will, Your Step-Children Inherit Nothing
The intestacy rules completely exclude step-children. A will is the only way to ensure step-children inherit — and an IPDI trust structure can protect the surviving spouse while securing the home for the step-children. WillSafe will kits from £39.99.
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