In a ruling that should clarify the Inheritance Act 1975, the Supreme Court has overturned a Court of Appeal decision backing a woman who had been excluded from her mother’s will in favour of three animal charities.

In the judgment handed down this morning, the Supreme Court said the Court of Appeal erred when calculating reasonable financial provision and allowed the charities’ appeal against that decision. The ruling, unanimous with a supplementary judgment from Lady Hale, restores an original order handed down by District Judge Clive Million.

Ilott v The Blue Cross and Ors, centred on Heather Ilott, who had been excluded from her mother Melita Jackson’s will. Jackson left most of her estate, worth around £500,000, to three charities – The Blue Cross, the RSPCA and the RSPB. Jackson had excluded her daughter after she left home with a boyfriend as a 17-year-old.

Ilott challenged the will under the 1975 act and was awarded £50,000.

Both parties appealed: Ilott claimed she had not been awarded enough while the charities said there was no lack of reasonable provision in the judgment.

On appeal, Ilott, who is in her fifties, was awarded £143,000 - to buy the rented home she was living in - plus an extra £20,000 for additional income. The Court of Appeal said Ilott, who has five children and was on benefits and without a pension, was not given a reasonable provision in the will.

But today’s judgment strikes out that ruling and restores the original ruling. Ilott will receive the original £50,000 award.

Handing down the judgment, Lord Justice Anthony Hughes said it confirms existing case law that ‘appeal will not succeed unless the judge made error of principle’.

‘Neither side can make the appellate court to start again from scratch. This is a general rule that applies to this case and many others,’ he added.

In her supplementary judgment, Lady Hale described the present inheritance law as ‘unsatisfactory’. She said: ‘I agree with Lord Hughes that it was entirely open to him [District Judge Million] to make the order that he did, and just as it should not have been disturbed first time round it should not have been disturbed this time either.’

She added: ‘I have written this judgment only to demonstrate what, in my view, is the unsatisfactory state of the present law, giving as it does no guidance as to the factors to be taken into account in deciding whether an adult child is deserving or undeserving of reasonable maintenance. I regret that the Law Commission did not reconsider the fundamental principles underlying such claims when last they dealt with this topic in 2011,’ Hale added.

Paul Maddock, a solicitor at DWF, noted Hale's judgment on the current law and its ‘obvious failure to give clear guidance around what factors should be taken into account in deciding whether an adult child is deserving or undeserving of an award’.

He added: ‘Whilst adult children of a deceased will continue to be able to seek redress from the courts where a will or the rules of intestacy fail to make reasonable financial provision for them, this judgment is in fact likely to be welcomed by those who felt there was a need to rebalance the law in favour of the wishes of the testator.’

Gareth Ledsham, partner at top 100 firm Russell-Cooke Solicitors, said the judgment will be seen by some as ‘victory for testamentary freedom’.

It was never intended that the legislation should act as a springboard for disgruntled adult children to challenge their parents’ testamentary freedom, just because they consider a will’s dispositions to be unfair. The Supreme Court justices have confirmed this is the case.’

Jonathan Fowles, a trusts and property barrister at Serle Court, said: ‘Today’s judgment will be a welcome relief for charities. The Supreme Court recognised their reliance on legacies in wills and that claims under the 1975 act do affect their interests.

‘The court also acknowledged the significance of Mrs Jackson’s choice of charities, even though she had no connection with them during her lifetime. For those who desire to make a charitable gift on death, this aspect of the judgment supports their freedom to choice regardless of any previous involvement with those causes.’

Martin Oliver, a partner at Wright Hassall Solicitors, and who represented Ilott, said: 'Heather is naturally very disappointed with the outcome of the Supreme Court judgment. It has been accepted that Heather was entitled to bring a claim for reasonable financial provision and has received £50,000 from her mother’s estate.

'Some of the judges have found that the current law is unsatisfactory and this will no doubt raise broader questions in the future. Heather has never wanted to be in the limelight or to be at the centre of a legal debate which polarises public opinion.'