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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