When Good Estate Planning Goes Wrong: The Critical Importance of Execution
A recent High Court case involving the historic Boconnoc Estate in Cornwall is a powerful reminder that inheritance tax problems are not always caused by bad intentions or aggressive planning. Sometimes, they arise because implementation fails where the strategy itself was entirely sensible.
The Fortescue family had spent decades restoring the Grade II-listed Boconnoc Estate, preserving it as both a family legacy and a working luxury wedding venue. Following the death of Anthony Fortescue in 2015, his widow Elizabeth inherited a life interest in the trusts holding the estate.
In 2017, after taking professional advice, Elizabeth attempted to release her interest in £4.4 million of estate assets to one of her daughters in a way intended to avoid inheritance tax provided she survived seven years.
The planning objective itself was straightforward and legitimate.
However, despite the original tax advice being correct, errors in the implementation process resulted in an unexpected £1.2 million inheritance tax charge.
The High Court ultimately intervened and set the transaction aside, with the judge concluding that the mistake created a “grave and unintended” tax consequence and that allowing it to stand would threaten the future of the estate itself.
Importantly, the court accepted this was not artificial tax avoidance.
It was described as:
“plain vanilla tax mitigation gone wrong.”
That distinction matters.
Too often, estate planning discussions focus only on products, structures or tax outcomes, while overlooking the most important issue of all: execution.
This case highlights several issues we increasingly encounter in practice:
• Correct advice can still fail through poor implementation;
• Tax planning without coordinated execution creates serious risk;
• Family estates and businesses are often asset-rich but cash-poor;
• Large unexpected tax liabilities can force distressed sales of property or long-held family assets;
• Legacy planning is not a one-off transaction but an ongoing process requiring oversight and review.
The court recognised that the estate had been “the subject of careful arrangement in order to create a lasting legacy.” In many ways, that sentence captures the real purpose of estate planning better than any technical tax discussion ever could.
At iTrust121, we believe proper planning should not stop at advice alone.
The real challenge is ensuring that planning is:
• properly structured;
• correctly implemented;
• regularly reviewed; and
• supported by the right professional oversight throughout its lifetime.
This is precisely why professional trustee involvement, ongoing support, and joined-up implementation matter so much in modern estate planning.
A strategy may look perfectly sound on paper. But if execution fails, even entirely legitimate planning can create catastrophic outcomes for families, businesses and estates.
As Senior Counsel to iTrust121, one of the most common misconceptions I encounter is the belief that once documents are signed, the planning is “done.”
In reality, the greatest risks often arise afterwards:
during implementation, variation, transfer, administration, and generational transition.
The Fortescue case is not simply a tax story.
It is a reminder that preserving wealth, property and family legacy requires more than technical advice alone. It requires a structured system capable of carrying that intention safely through every stage of the planning journey.
James Berkeley
Senior Counsel
iTrust121