A former City high-flyer who gave up work to care for his frail mother - only to end up homeless and destitute after a row with his 80-year-old millionaire dad - is now fighting him in a £2m court battle.Harry Lambert, 42, had carved out a successful career as a private equity specialist and was renting a plush apartment in exclusive Canary Wharf when he returned home in 2023 to help care for his elderly mum at his father's request, he told London’s High Court.Before moving back into the family house in Buckingham Road, Redbridge, his father “promised to provide him with long-term secure accommodation,” he says.But he ended up living "on the street" he says, after tensions got so bad between him and his father - retired teacher Christopher Lambert - that his dad changed the locks to bar Harry from the house whilst he was out for a run.Following his mum's admission to a care home but before she died, Harry was kicked out, he told a judge, and is now in a council-run HMO flat, where he can't work because of his living conditions.Christopher's barrister Mina Heung confirmed outside court that it is part of Harry's case that his dad changed the locks on the house after he had gone out for a run.Harry Lambert outside High Court after hearing in house row with dad Christopher Lambert (Champion News)He is now suing his dad for a portion of the wealth acquired by his parents, claiming that his mother left assets valued at around £2m, and to force his dad to let him back into the family house to live.But his father, who inherited all Mrs Lambert's money on her death, hotly disputes the amount Harry says the family fortune is worth and denies making any promises that his son would be financially "looked after".Judge Richard Farnhill heard Harry claim that his dad turned against him when they clashed after the retired teacher sold one of the family’s properties in Clementine Walk, Woodford Green, without handing any of the profits to his son, as he had allegedly promised.Harry insists that by returning home he had lost out on earnings, given up a solid tenancy and then contributed towards household expenses while helping to care for his mum, and was assured that he would be financially “looked after” in return.In June 2025, Harry’s dementia-stricken mother, Maureen, was admitted to a care home, and soon afterwards in August his dad changed the locks on the front door and barred him from the family home in Buckingham Road.The late Maureen Lambert - mother of Harry Lambert and wife of Christopher Lambert, who are locked in court fight over house (Supplied by Champion News)Maureen died the following month and in her will left her entire estate to her husband, the court heard.After being turfed out, Harry claims he ended up temporarily living “on the street” before moving into a council-run multi-occupation flat, where he currently remains.The "destitute" ex-financier is now suing his elderly dad in a bid to secure a slice of the fortune he says he was promised, and to win the right to return home.“I want to be back in my house and in my bed where I was living for 20 months and which has been my family home for 40 years,” he told the judge.“I’m now living in an HMO flat in Dagenham with no WiFi and so no ability to do a job which relies on having access to the Internet.“I’ve not been earning and I’ve been on universal credit, I’ve been reduced from an earning capacity of £100,000 per year to being poor.“I can’t even eat most nights.”Harry is seeking a court ruling that he is entitled to a 50 percent share in the Buckingham Road property, as well as bringing an “estate-wide” proprietary estoppel claim over family assets.The house in Buckingham Road, Woodford Green, at centre of dispute between Harry Lambert and dad Christopher Lambert (Supplied by Champion News)His dad’s failure to share the profits of sale from the Clementine Walk property “caused considerable friction between Harry and his father, and soon after that happened their relationship started to break down,” the judge told the court as he sketched out Harry’s case.“In February 2025, his father told Harry to leave the property, but he didn’t do so. Over the next few months, Christopher Lambert installed locks on the internal doors, excluding his son from areas such as the kitchen."With the trial of Harry’s claim on the family money pending, his case reached court as he applied for an interim order allowing him “exclusive” use of the house, with his father having to leave, or an alternative order requiring his father to fund his accommodation to the tune of £3,500 per month.“I’m asking for reinstatement into the property and my father’s exclusion, as we cannot co-habit," he told the judge.“He hasn’t been in the property most of the time, he has been abroad travelling, but my fall-back position is that he should fund temporary accommodation for me until trial.”Ms Heung, for the dad, argued that it would be “draconian” if he ended up being barred from his own home of 40 years and dismissed Harry's argument that his dad can go to another property he owns, in Cheyne Court, Woodford Green.Christopher Lambert outside High Court after hearing in house row with son Harry Lambert (Champion News)Branding Harry’s application “intrusive,” she argued: “he seeks not merely to enter the property, but to occupy it as his sole or primary residence and exclude his father from his own home.“The parties’ relationship has broken down seriously,” she continued.“Harry’s own evidence refers to family conflict, police involvement, non-molestation proceedings, allegations of criminality, lockouts, deadbolts, safeguarding allegations and disputed financial matters.“A mandatory order placing Harry back into occupation while excluding the legal owner will be highly likely to generate further disputes and applications.“Harry says his father can live at Cheyne Court or has been abroad. That is not an answer.“The alleged availability of another property does not entitle him to occupy his father’s home - nor does his father’s travelling abroad from time to time mean the property is abandoned."The barrister also said the dad “denies making any clear, binding or irrevocable promise giving Harry a proprietary interest in any property or asset”.Ms Heung confirmed outside court that it is part of Harry's case that his dad changed the locks on the house after he had popped out for a run.After two hours in court, the judge refused Harry’s application to exclude his dad from his property and move back in, also declining to order that he cover his son’s rent.However, he directed that the trial of Harry’s wider claim should be heard as soon as possible and said he should be given access to Buckingham Road to recover what he claims is property worth tens of thousands of pounds, including a collection of rare plants.