With its elegant navy door, Victorian-era gault brick facade, and heavy velvet curtains pulled across the front windows, this house appears to blend seamlessly with its upscale Chelsea surroundings. In this verdant, highly sought-after area, homes typically fetch between £3 million and £4 million, ranking it among the most desirable neighborhoods in London.

However, a closer inspection reveals a different story. The steps leading to the entrance are marred by cracks, weeds, and signs of moisture.

Several front railings have collapsed, leaving a hazardous gap that has been temporarily covered with yellow plastic tape labeled ‘Environment Agency Aware.’ Debris litters the stairway to the basement, where a shattered window has been hastily boarded up. Inside, piles of black garbage bags mingle with stacks of books, furniture, canned goods, and cardboard boxes.

Out of sight from the street, the situation in the backyard deteriorates further.

Japanese knotweed, a notoriously invasive species known for damaging foundations, brickwork, and concrete, has taken over, transforming the lawn into an overgrown thicket.

Neighbors claim it has been left unchecked for over ten years, now reaching heights of 10 feet and encroaching on adjacent properties. This rampant growth is causing significant damage and diminishing the value of their million-pound homes.

And this is not the only nasty surprise hidden behind this otherwise-ordinary looking façade.

Leaking drains have, allegedly, turned the ground floor of the house into a ‘swamp’, while rats and foxes have taken up residence inside – and started breeding. Neighbours claim they are kept awake by screeches from mating foxes, who chew through garden lights and defecate daily on the pavement outside.

In a final twist to this repugnant tale, a rotting human corpse was removed from the basement several years ago, after locals complained about the smell. Such was the nightmarish scene inside that several policemen vomited on arrival.

One might assume, as many families on this friendly, residential street did at first, that a house as dilapidated as this must have been abandoned. But there is an owner, who doesn’t live in the property but visits regularly, his presence confirmed by a light going on in a room on the first floor.

Nicholas Halbritter, 78, has owned the house for 42 years – and appears to have stood by and let it go to ruin for almost half this time.

As chairman of the Kensington and Chelsea branch of the Royal British Legion, he is a dedicated poppy-seller and fundraiser, as well as a devoted member of the Friends of Brompton Cemetery, where he gives guided tours.

He was once a Conservative councillor for the area, serving on committees overseeing education, the arts and children’s services, between 2002 and 2006.

In 2022, Mr Halbritter – who is believed to be a former architect – even received an award from the mayor of the borough in recognition of his fundraising efforts for war veterans. And the following year he posed on the steps of 10 Downing Street, where he attended a reception in honour of the Armed Forces.

On paper, at least, he seems an upstanding and well-respected member of the community. But residents who live on the same street as Mr Halbritter describe him as a ‘neighbour from hell’.

Speaking to The Mail on Sunday this week, next-door neighbour Christine Gambles, 69, who has lived here for 26 years, says she has tried several times to approach him about the state of his property.

‘He beetles up the street and runs in the door,’ she says of Mr Halbritter. ‘If I ask him for a conversation, he literally slams the door in my face.’

Keen to sell her home after the death of her husband, John, four years ago, she fears the spreading knotweed and damp on walls that adjoin Mr Halbritter’s property – a result, she assumes, of mould and leaks on his side – mean she cannot.

‘I feel completely stuck,’ she adds.

Nik Hoexter, who has lived on the other side of the house for 40 years, describes it as ‘a sordid place’. ‘It’s become a nightmare scenario,’ he adds. ‘All the neighbouring houses have to overlook this shambles – and it’s only getting worse. Underneath all that vegetation there’s a Second World War bomb shelter in his garden.

‘This has gone far beyond a disagreement between neighbours; it’s a blight on the whole street.’

He, Christine and others have been complaining to Kensington and Chelsea Council – the very same body on which Mr Halbritter once served – for years, and recently set up a petition, which has been signed by almost 50 residents, begging for resolution.

So far, they say, nothing has been done. ‘How bad do things have to get for the council to act?’ Nik Hoexter asks.

Shockingly, The Mail on Sunday can reveal that this multi million-pound mansion isn’t the only property owned by Mr Halbritter, which has become a hazardous eyesore. Six miles away, in trendy Camberwell, south-east London, is another derelict house – this one worth around £1 million – which has allegedly been left to rot. Until recently, Mr Halbritter owned this three-storey property and the one next door.

With boarded-up windows, a rubbish-strewn garden and a roof that caved in several years ago, the house appears to be in an even worse state than his Chelsea one.

A builder at the adjacent property, who says the owner bought it from Mr Halbritter last year, described him as ‘a bit eccentric’.

‘He had left it derelict for 20 years and the neighbours were furious,’ he added.

So just how did things get this bad? Very little is known about Mr Halbritter, who cuts something of a mysterious figure most residents of the Chelsea and Camberwell streets haven’t spoken to in years. Unmarried, with no children, his family lived in Devon and later Wales. He was born in London in 1947 and has a younger sister.

His father, Sidney, was an architect, and it is thought that Nicholas followed in his footsteps.

His mother, Elizabeth, was a housewife, who once pleaded guilty to shoplifting cashmere jumpers, scarves, handkerchiefs and children’s clothes from shops including Liberty and John Lewis.

After his father’s death, Elizabeth appears to have moved into the Chelsea house with Nicholas; her name is listed alongside his in Land Registry documents relating to the basement flat in 1998.

In 2002, there was a bankruptcy filing for him. Then, in 2008, his beloved mother passed away.

This, neighbours believe, is when Mr Halbritter’s properties began to fall into disrepair. At some point, perhaps to help with the household bills, he began letting out parts of the Chelsea house to lodgers, and appears to have moved elsewhere himself. Around 2010, one of them, an Irish builder in his 60s, lived in the basement flat. Tragically, his was the body that was found later that year.

It was so badly decomposed that he had clearly been dead for some time. There is no suggestion Mr Halbritter neglected his duties towards his lodger in any way, nor that he knew of his awful fate – but neighbours say the flat was already in a bad way.

‘It was in a terrible state,’ says Nik Hoexter, whose daughter – who lives in a self-contained flat within his house – smelt the body and called the police. ‘There was no inside lavatory – just a hut, which is now rotten and covered in knotweed. The flat would have been cold, damp and deeply unpleasant.’

Though alarmed by the grisly discovery, neighbours had no idea that things would only get worse. Over the following years, Japanese knotweed in the back garden spread uncontrollably, leading to so many complaints that the council served Mr Halbritter with a Section 215 enforcement notice under the Town and Country Planning Act 1990, in August 2016.

This included an itemised list of ten repairs, including sorting out the knotweed, fixing doors and windows and removing rubbish from his basement area and garden.

Having failed to carry out the work by the deadline, the following May he pleaded guilty to failing to comply with the notice and was ordered to pay £1,513 in costs.

Mr Halbritter, who represented himself at Hammersmith Magistrates Court, claimed he had been ‘misled’ by the council, who had promised him several months’ grace in fixing the problems. ‘I am very devoted to the British Legion Poppy Appeal,’ he told the court. ‘And each year I set three months aside, the last three months of the year.

‘I am actually the deputy organiser for the whole of Kensington, and it’s an extremely busy time of year. I have about 45,000 poppies delivered to my home.’

He claimed his monthly income was ‘not that high’, so he was ordered to pay the amount due in £60 monthly instalments. He also insisted he had approached a specialist contractor to remove the knotweed – and pledged he would clean up the mess before the summer. Yet nothing, neighbours insist, was done. Indeed, one has shared a photograph which appears to show Mr Halbritter digging up the plant himself, rather than employing an expert. Thereafter, his back garden jungle – and the mounting miles of rubbish and waste – was simply left to spiral out of control.

The same was true at the Camberwell properties, where, early last year, another enforcement action was brought against Mr Halbritter. There, he was ordered to pay court costs of £2,317 in relation to both houses.

While the one he sold is being renovated, the derelict state of the property he still owns suggests no remedial action was taken.

There was no answer at either of Mr Halbritter’s houses this week, nor did he respond to repeated attempts to contact him by email.

A neighbour in Chelsea, who did not want to be named, said: ‘If anyone tries to approach him, he does a runner.’

But tailor Ash Ahmed, who owns a shop on the street, describes him as a ‘nice man’, who regularly pops in for alterations and is a familiar figure selling poppies outside the nearest Tube station.

‘He’s a normal, friendly person,’ he says. ‘Maybe he doesn’t have any help or enough money to maintain it [the Chelsea house]. Maybe he feels bitter because people are not talking nicely about him.’

Indeed, it is not so much towards Mr Halbritter as towards the council that locals’ ire is directed.

‘I would describe them as inept, unprofessional, ignorant of their powers, and absolutely uncaring as to the situation the whole street is being put in,’ says Christine Gambles. Susan Bent, 65, who also lives on the street, added: ‘I don’t understand why they haven’t got involved. If you put a bin out on the wrong day you get in trouble.’

Ben Coleman, Labour MP for Chelsea and Fulham, described the council’s behaviour to date as ‘baffling’. ‘It’s a grim and grotesque situation,’ he said last week. ‘The council seems to spend more time brushing the issue under the carpet than resolving it.’

For its part, a spokesperson for Kensington and Chelsea Council said the issue dated back an ‘extremely long time’ and that its officers had been in touch with Mr Halbritter ‘for many years’.

The last time they spoke to him directly, however, was last year – and only on the telephone.

‘Our planning enforcement and environmental health teams have exhausted their powers and provided advice to the property owner,’ the spokesperson added.

‘There is a very high bar for enforcement action on private property and this property is not in a condition that would justify further action.’

They added that councils have no power to eradicate foxes (or indeed rats) on private land, and that reports of the leak have been passed to Thames Water. As for the plant at the root of it all, the spokesperson said there was ‘no conclusive evidence’ the vegetation in Mr Halbritter’s garden was Japanese knotweed.

This directly contradicts statements made in emails a council official sent to residents who complained about the issue last year. These emails have been seen by The Mail on Sunday.

In addition, photographs taken last week of Mr Halbritter’s garden, and inputted into PictureThis, the leading plant identifier app, confirm that the shrub is Japanese knotweed. When this was put to the council, the spokesperson insisted that, even if it is knotweed, landowners are not legally required to remove it from their property unless it spreads. This is despite issuing an enforcement notice to Mr Halbritter around that very issue in 2016.

‘Quite how they have lost the powers they seemed to have nine years ago is very concerning,’ says Nik Hoexter. ‘It’s the same old story. They come, they shake their heads – and they do nothing.’

Despite repeated requests, Kensington and Chelsea Council officials were unable to accompany The Mail on Sunday to inspect the property this week. For now, it seems, this knotty neighbourly drama is doomed to continue behind closed doors – and in Mr Halbritter’s ever-expanding back garden.

Additional reporting: Stephanie Condron.