A woman has won a £2m inheritance claim after a solicitor’s cat knocked over a pile of papers to reveal the will of her late brother, which had been missing for two decades.

Venetia Murray and her brothers, Dean and Dale Brunt, had owned a farm at Broxbourne in Hertfordshire which was valued at £6m. They had inherited the property from their grandfather, Arthur Nicholls, who had bought it with earnings he had made as a champion prize-fighter.

When Dean died in an accident on a local railway line in 2007, aged 35, his relatives presumed he had not made a will. As a result, his £2m share of the farm went to his 82-year-old mother, Marlene Brunt, who later handed it on to her eldest child, Dale.

However, Ms Murray later discovered that Dean had made two wills in 1999. One of these, containing what lawyers termed “crucial evidence” of Dean’s intention to give his sister half his wealth, was only found when a solicitor’s cat overturned a pile of papers that were due to be shredded during an office clear-out.

Last week a High Court judge rejected claims by Dale and his mother that the wills were forged and part of an “elaborate fraud”; ruling that Ms Murray would inherit half of Dean’s share of the farm.

Judge Paul Teverson said he was satisfied that Dean had approved the 1999 wills and ordered that the dead man’s estate should be divided according to their directions; splitting his share of the farm equally between Dale and Ms Murray. Dean’s share of a house on the land was passed on to his uncle, Bob Wrangle.

Although experts commented it was possible both of the wills might have been written more recently than the 1990s, Judge Teverson said there was a “substantial amount of evidence” that Dean had talked about having made a will in the years prior to his death.

He had told friends he had done what his grandfather would have wanted, leaving his share of the farm to his brother and sister, with his mother getting nothing.

The judge added that he found Ms Murray to be an “impressive witness”. “I do not think she would for one moment associate herself with a fraudulent claim,” he added.

Mrs Brunt, on the other hand, he found to be a “most unimpressive witness”, and suggested that she had deliberately kept both Dale and Ms Murray in the dark about Dean having “died intestate”.

The judge added: “Looking at the totality of the evidence before the court, I am satisfied Dean had understood what was in the will and did approve its contents.”