How to ensure your son and stepson inherit equally if you die first
A reader with mirror wills wants to ensure that both his son and stepson inherit equally after he and his wife pass away. While mirror wills are a common starting point for couples, they contain a significant flaw that could undermine his intentions.
The fundamental problem is that mirror wills are not legally binding on the surviving partner. After the first death, the surviving spouse typically remains free to change their will entirely, potentially disinheriting the children or stepchildren named in the original arrangement.
This concern is far from theoretical. Recent research from STEP (Society of Trust and Estate Practitioners) reveals that 41% of practitioners have seen an increase in inheritance disputes within blended stepfamilies, with 71% identifying complex blended families as the leading cause of legal challenges to inheritance. Conflict between children or stepchildren and a surviving parent or stepparent is the most common source of friction, cited by 68% of estate practitioners.
With nearly 30% of UK marriages now second or subsequent marriages, this structural complexity in inheritance planning affects a growing proportion of families. The reader's proactive approach stands in stark contrast to the broader picture: STEP research found that around 19 million UK adults have no will at all, while approximately 44 million lack clear communication regarding their final wishes.
Life interest trusts offer protection and security
Louise Lewis, partner and head of trusts, estates and tax at Freeths law firm, explains that a life interest trust is often the most appropriate solution for blended families. This arrangement allows a surviving spouse to continue benefiting from assets during their lifetime while preserving the underlying capital for beneficiaries chosen by the first spouse to die.
In practical terms, a share of the family home could be held in trust, enabling the surviving spouse to continue living there for the rest of their life. The crucial difference is that the share ultimately passes to the intended beneficiaries rather than becoming the surviving spouse's property to dispose of as they wish.
Similarly, if investments form part of the estate, the surviving spouse could receive any income generated by those assets without owning the underlying capital outright or being able to redirect it through a future will.
An important advantage for married couples is that life interest trusts for spouses or civil partners benefit from spousal exemption for inheritance tax purposes. This typically means no inheritance tax is due at the first death, with HMRC treating the life tenant as if they own the trust assets.
Discretionary trusts provide flexibility
Another option is a discretionary trust, which Lewis says is regularly used in blended family situations because it gives trustees flexibility to respond to changing circumstances. Rather than assets passing outright to one beneficiary, trustees can decide how and when funds should be distributed between a group of beneficiaries, which might include a surviving spouse, children, stepchildren and even future grandchildren.
This flexibility can prove particularly valuable because family circumstances rarely remain static. Over time, one child may become financially comfortable while another faces challenges such as ill health, relationship breakdown or difficulty getting onto the property ladder. Discretionary trusts allow trustees to take these evolving circumstances into account when making decisions.
These trusts can also provide a degree of asset protection, as assets remain within the trust rather than passing outright to beneficiaries immediately. In some cases, this helps safeguard family wealth from risks such as financial mismanagement, undue influence or creditor claims.
However, discretionary trusts do come with tax implications. They are subject to periodic inheritance tax charges every ten years at a maximum rate of 6% on trust assets exceeding the nil-rate band, which currently stands at £325,000.
Choosing trustees and providing guidance
Whatever structure is chosen, selecting the right trustees is crucial. They will be responsible for making important decisions long after your death, so it is vital to appoint people who are trusted to act fairly and balance the interests of everyone involved. Some families choose a combination of family members and a professional trustee to provide both personal insight and independent oversight.
Many people also prepare a letter of wishes alongside their will. While this is not legally binding, it provides valuable guidance to trustees about how they would like decisions to be made as family circumstances evolve. The letter can be updated at any time without the cost or formality of changing the will itself, making it a flexible tool for expressing intentions that may shift over the years.
Lewis concludes that if equal provision for both sons is important, relying on mirror wills alone may not provide the certainty needed. Taking advice on a trust-based will can help ensure wishes are protected while also providing financial security for a surviving spouse.
The reader may wish to return to the solicitor who drew up the original wills, or use the Law Society's search tool to find a firm experienced in this area of estate planning.
