Britain's second wealthiest family, the billionaire Hinduja brothers, are in court in a dispute over their £16bn (Dh73.62bn/$20.04bn) assets. The brothers, originally from India, are based in London and have lodged proceedings at the High Court over a disputed letter from 2014. Court papers reveal Srichand Hinduja, 84, described as the patriarch of the family, is taking action against his brothers, Gopichand, 80, Prakash, 75, and Ashok. The dispute centres on a letter that was signed by all four brothers in July 2014 stating that “assets held in any single brother's name belong to all four”. Within a year of it being signed, Srichand appointed a legal team to take action to "disavow" it. A year later he made a witness statement declaring "the July letter does not reflect his wishes and that the family's assets should be separated". His brothers have sought to use the letter to take control of Hinduja Bank, an asset in his name alone, the court heard. The brothers co-chair the India-based Hinduja Group, which deals in banking, oil and property. The group recently bought former prime minister Winston Churchill's Old War Office, near Buckingham Palace, for £350 million and is turning it into a flagship five-star Raffles hotel. On Tuesday, Mrs Justice Falk heard details of the dispute at the Royal Courts of Justice. "The parties are brothers, Srichand Hinduja being the eldest and the current patriarch of the family," she said in outlining the case. "The substantial business empire controlled by the family was originally founded by the parties' father. "These proceedings are brought to determine the validity and effect of a letter dated 2 July 2014, signed by Srichand Hinduja and the defendants, together with a further letter apparently from Srichand Hinduja dated 1 July 2014. "The 2 July letter includes statements to the effect, among other things, that the brothers appoint each other as their executors, and that assets held in any single brother's name belong to all four. "The further letter states that Gopichand, Prakash and Ashok are authorised to carry out all steps to implement the other letter. "In summary, Srichand Hinduja seeks a declaration that neither document has legal effect, whether as a will, power of attorney, declaration of trust or other binding document, or alternatively that the documents are revocable and have been revoked." The family are also locked in further disputes with each other in Jersey and Switzerland. The UK case was initially lodged last November. Ms Falk has appointed Srichand Hinduja's daughter Vinoo to conduct the proceedings on his behalf amid claims he is suffering from dementia. The court heard she had been accused of having a "financial advantage" in representing her father, but the judge ruled she had "no concerns" over allowing Vinoo to act as his litigation friend. "It is said on Srichand's behalf that, if the defendant's position on the July letter is correct, then that throws Srichand's estate and tax planning into disarray, calls into questions the validity of his wills, potentially displacing the appointment of his executors, and may also make the acts of his attorneys invalid," Mrs Justice Falk added. “If any part of this is right, and I did not understand the assertion to be challenged, then proceedings that seek to determine the legal effect of the July letter, and address the uncertainty that currently exists, cannot rationally be said to be contrary to Srichand's interests.” “In principle it must be in Srichand's interests to have the effect of the July letter definitively determined, and these proceedings would appear to be an appropriate step for his attorney to take on his behalf.” This year the Hinduja brothers were knocked off the top spot of <em>The Sunday Times </em> Rich List, after it claimed they had suffered £6bn losses. They have moved down to joint second position alongside property developers Simon and David Reuben with £16bn. The Hinduja Group was initially founded by the brothers' father, Parmanand Hinduja, in 1914 in Mumbai. It has its headquarters in London and employs about 150,000 people worldwide.