Blended families and mirror Wills: the accidental disinheritance trap

More families than ever are blended: second marriages, stepchildren, children from previous relationships. The estate planning wish is almost always the same - everything to the surviving partner, then shared between all the children. And the standard tool, a pair of simple mirror Wills, quietly fails to deliver it in two separate ways.

Failure one: "my children"

In a Will, "my children" means your own children - stepchildren are not included unless the Will says so. In mirror Wills that leave everything to the survivor and then "to my children", whichever partner dies second passes everything to their own children only. Half the family disinherited by two words.

Failure two: the survivor's freedom

Even perfectly drafted mirror Wills are only promises. The survivor can rewrite theirs at any time - and if they remarry, their Will is revoked automaticallyThe survivor can rewrite theirs at any time - and if they remarry or enter a civil partnership, their Will is revoked automatically, with the intestacy rules then favouring the new spouse. Care fees and creditors can also consume what was informally earmarked for the first family's children. Nothing in a simple Will binds any of it.

What actually works

The reliable structure is a Trust in the Will: the first estate is ringfenced for the intended children, while the surviving partner is provided for - typically including the right to remain in the family home. Provision and protection, instead of provision or protection. Beneficiaries are named deliberately, so "all our children" means exactly that.

Key takeaways

• "My children" excludes stepchildren unless the Will says otherwise
• A survivor's Will can be rewritten or revoked; promises do not bind it
• A Trust delivers "partner first, then all the children" - a mirror Will cannot

If yours is a blended family with simple mirror Wills, a complimentary review by a STEP-qualified estate planner will show you what your Wills actually do.