A former contestant on The Apprentice is being sued by his neighbours over three feet of land in between the £1million homes.
Tea boy turned high-flying estate agent Alex Britez, 39, appeared on the seventh series of Alan Sugar's show in 2011.
He was booted off by Lord Sugar, who labelled him a "good talker."
Now Mr Britez is being sued by David and Isabel O'Brien, his next-door neighbours, over a tiny passageway between their London homes.
The row started in 2018 when builder Mr O'Brien's stepdad Roy Curtis fell into a hole, which Mr Britez's mum had dug into the passageway alongside her home 15 years earlier.
The O'Briens have taken it to court claiming the trench is dangerous.
They also claim that the entire passageway between the houses belongs to them anyway.
Mr Britez is arguing that the true boundary between their homes runs down the middle of it.
During his 2011 appearance on the BBC show, Mr Britez described himself on the show as "ambitious, driven, and extremely focused".
He now works as head of sales for a major property development company.
Recorder Cheryl Jones, at Central London County Court, heard that Mr Britez has long lived at the house in affluent Dulwich, South London, which previously belonged to his mum Mary Britez.
Mr O'Brien, 52, and Mrs O'Brien, 47, moved into the next-door four-bedroom semi-detached house in 2015.
The two properties are separated by a narrow, gated passageway.
In 2007, the surface had been dug up to a depth of a few inches along the length of Mr Britez's wall due to damp issues in his home, which sits below the level of the alley in the steep street, the court heard.
The neighbours were initially on good terms, but the row blew up after 2018 when Mr O'Brien's stepfather fell into the trench.
The barrister for the O'Brien's said the "rather haphazard" trench effectively narrows the useable width of the passageway and that Mr Britez and his mum, who had ordered the work when she owned the house, insisted that it remains open.
He said: "The consequence is that the surface of the passage is now very narrow, and is dangerous. Something needs to be done.
"Mr and Mrs O'Brien wish to be able to use the passage safely, as it was used for very many years [before the trench was dug].
"However, they recognise that Mr Britez wishes to avoid a recurrence of the damp."
He said Mr O'Brien had suggested that a metal grate could be installed over the trench, but it was rejected by Mr Britez.
He also argued that the true boundary between the two properties is the wall of Mr Britez's house, so that all of the passageways belong to the O'Briens.
Alternatively, they say they have a right of way over the whole width of it and that Mr Britez is under a duty to make the trench safe.
Giving evidence, Mr O'Brien said "not for one second" did he think he might not be buying a house that came with the entirety of the passageway alongside it.
He said the neighbours had been "friends to start with" and they had good relations, with no hint of any disagreement over who owned the passageway.
Their conversations had been about how to make it safe, not about where the boundary was, he told the judge.
He told the judge: "I was led to believe that Britez had a damp problem and could see no problem in fixing it - that's what I do for a living all of the time.
"We had a discussion in the garden about how we were going to fix the problem.
"At the time, Alex was quite happy that my solution was a good solution. There was no talk of a boundary. It was about making it safe.
"I was talking about filling and making the hole safe right from the off.
"It just needed to be done faster because I didn't want anybody else to fall into the hole."
Mrs O'Brien added that she never thought she had a "boundary issue," adding: "We were just trying to make the area safe."
"It's totally logical that we own the passageway, given that its sole purpose is to access our garage and rear garden," she continued.
Mr Britez's barrister Simon Brilliant said it is his case that the boundary is somewhere along the middle of the passageway.
He explained that an old wall buried below the surface was likely the true boundary line. He added that the previous owner agreed that when the trench was dug.
He argued: "The whole purpose of the excavation was to create a gap...It was intended to be permanent.
"There was no suggestion that anyone at the time envisaged that it would be filled within a short or any time frame."
He added: "It is regrettable and disappointing that despite having been told in the clearest terms before they purchased that they did not own the disputed land, they have years later now chosen to assert otherwise.
"They were quite content to live under a regime whereby the excavated land could not be used by them. It was not until summer 2018 that they questioned the ownership of the disputed land."
He said Mr Britez had offered to erect a railing down the middle of the passageway to prevent anyone else from falling into the trench but denied that it was dangerous as it is.
"Given that there was no accident between 2007 and 2018, it is submitted that the disputed land is not unsafe," he said. "It is perfectly safe, providing all reasonable care is taken when walking down the passageway."
The trial continues.
