Seven years ago Louise Lotz wrote a letter to her local council asking to cut down a tree in the back garden of her £500,000 terraced home.

It was, she explained, so overgrown that it was posing a danger not only to her house but to the one next door as well.

'My neighbours have kindly submitted a planning application on my behalf for permission to remove the silver birch on the boundary of our two properties,' she wrote. 'I am writing in full support of this application, which we have discussed in detail.'

No doubt just the sort of community spirit the founders of Welwyn Garden City had in mind back in the 1920s when they set about building the genteel Hertfordshire 'new town'.

But fast forward to last summer and to say that relations between Miss Lotz and neighbour Debby Foxwell had taken on a decidedly 21st century turn could hardly be more of an understatement.

By then neighbourly cups of tea had been exchanged for endless arguments, which ended in court yesterday when Debby Foxwell, a privately educated, 41-year-old company director, was convicted of murdering her neighbour.

She had battered the 64-year-old former Lib Dem councillor to death with a spade, as their feud over a garden fence exploded into open warfare and violence.

Privately educated company director, Debby Foxwell (above), was convicted of murdering her neighbour Louise Lotz

The week-long trial at St Albans Crown Court was told the pair had squabbled for at least six years. As one neighbour put it: 'We had just got used to it. It was like hearing dogs barking.'

It started with a petty spat over an adjoining fence which Foxwell claimed had encroached on her property by a matter of inches.

She'd been quick to confront Miss Lotz about the matter and words were exchanged. Over time, words descended into actual physical assaults, which once left South African-born Miss Lotz needing hospital treatment.

Police were involved on that occasion – and numerous others – and kept a running log of their disputes, over bins, boundaries and general tidiness.

Miss Lotz, who lived at No 8, was described by witnesses as an 'untidy hoarder' whose house was a mess, while Foxwell's garden at No 10 was 'perfect'.

By last August it was pretty much open warfare. Foxwell, by then, was convinced that attempts to sell her house had been scuppered by her neighbour's scruffy property

Prone to moods of 'white, hot anger' Foxwell had developed a 'visceral hatred' towards Miss Lotz.

Following yet another row, Foxwell armed herself with a shovel and barged into the next-door house where she first demolished a plasma television and a laptop.

Spotting Miss Lotz running out of the house, she left in pursuit, shouting: 'There is the bitch.' As Miss Lotz banged on a neighbour's door, Foxwell struck her on the head seven times with the spade – turning it on its side to use like a machete – before returning home.

'It's over. I have done it,' Foxwell calmly told her partner as she walked away following the 'sustained, brutal and merciless attack'.

Louise Lotz (above), a 64-year-old former Lib Dem councillor, was beaten to death with a spade, as their feud with her neighbour over a garden fence descended into violence

After she was arrested, it would be claimed that Foxwell was suffering from a borderline personality disorder: she admitted manslaughter on the grounds of diminished responsibility, but was found guilty of murder.

But, as the Mail discovered, there is a tragic back story to both of these women, leading up to their bloody and fatal clash in this Home Counties suburb last summer. Miss Lotz had been overseeing the care of her autistic 55-year-old brother, whom she'd fought to bring to the UK.

'The most tragic aspect of it all is that the only survivor is the most vulnerable,' a family friend revealed. 'He has seen everyone he loved die one by one and now he is the only one left.'

Those who know Miss Lotz say she had had to continually battle to get her brother the care he needed – showing the sort of fighting spirit that she first had to display as a young girl growing up in South Africa

Born Marietta Lotz – she was known as Louise – at the age of seven her policeman father Andre died of a heart attack, leaving mum Marie in dire straits without a job and with five children to feed. Miss Lotz and her siblings were placed with a foster family when she was 14.

Despite her change of circumstances, she proved to be an A-star student, graduating with first class honours degrees in English Literature and Fine Art from The University of Cape Town. There she met and fell in love with brilliant fellow student David Reid, a chemist.

She qualified as a teacher and the pair married, moving to England when Mr Reid won a prized Rhodes scholarship to Oxford University.

The couple had two children, but their youngest son was struck down by leukaemia and died at the age of seven.

'When he died their marriage began to just disintegrate,' the South African friend told The Daily Mail. 'It never recovered and they separated and they moved on to their own careers and own lives.'

For Miss Lotz, the friend says, that included ensuring that her younger brother was well looked after. 'About 20 years ago she began a very tough and long fight with the UK immigration authorities and with the National Health Service to have him come to live in the UK,' she said.

Debbie Foxwell's home (pictured left) is next-door to Louise Lotz house (pictured right) on a tree-lined street in Hertfordshire

'She wanted to be his carer and she faced lots of red tape and slammed doors but finally about 15 years ago she won her case and her younger brother flew to the UK for good.'

Home for the pair of them would be Welwyn Garden City and the three-bed-property that Miss Lotz purchased in 2008.

In that same year she would be elected as a Lib Dem councillor, serving for three years before switching her allegiance to the Green Party.

She also worked in disability rights and as a massage therapist, sometimes helping at a local hospital giving massages to oncology patients.

It was in 2012 that new neighbours arrived on the scene – Foxwell and her then-partner Paul buying the adjoining house for £300,000.

They set about renovating the property but relations between the neighbours turned sour over a new fence erected in the back garden.

'Louise paid to have the fence put up professionally but the neighbour disputed where the fence went and said it was a couple of inches over where the line should have been,' said Marc Scheinmann, chairman of the Welwyn Hatfield Green Party, who witnessed the ill-feeling first-hand when staying with Miss Lotz several years ago.

'She [Foxwell] was attacking the fence all the time and trying to destroy it. There was shouting across the fence, lots of arguments.

'Louise was always scared of going out and would say, 'Marc, would you come out with me when we go to the car?'. She wouldn't go out in her garden because she didn't want to be shouted at – that's not a situation that should have been allowed to continue.'

And it was a situation that only got worse. In 2016 Mr Scheinmann visited his friend at the Lister hospital in Stevenage where she was being treated for a broken nose. 'Louise kept on saying it was done by the next door neighbour,' he said.

'She did complain to the police but she kept on saying she was frustrated that not enough action was taken.'

South African-born Mrs Lotz, pictured, was murdered by Foxwell who hit her with a spade

It is understood Foxwell was convicted for assault and criminal damage. Not that Miss Lotz was a shrinking violet herself – far from it. Friends describe her as 'feisty' and unwilling to back down from a challenge.

Susan White, her other next-door neighbour, described her as 'intimidating', claiming the former councillor had gone into her garden and pulled up plants and shrubs.

Miss Lotz was also accused of laying claim to a communal area in front of the houses and making a 'malicious' report to the RSPCA claiming the White's dog was being ill-treated.

While Foxwell herself did not give evidence, the court heard she was mentally fragile. She had attempted to take her own life on a number of occasions and, having been employed by the drugs company Roche, ended up running her own business support services firm from home because she had 'difficulty' with people.

She had also struggled to come to terms with the death of her husband who passed away suddenly in 2016.

Mr Foxwell died just four weeks after being diagnosed with cancer – but not before a special marriage licence had been arranged so that the pair could wed in the hospital chapel.

In the years that followed, friends say Foxwell struggled to cope, taking anti-depressants and seeking help from mental health services.

'She was not dealing with things well,' a friend said. 'There was an anger with the world.'

Foxwell wanted to sell her house and had put it on the market for £525,000. Its listing describes it as refurbished 'to the highest standards'.

But she feared the state of Miss Lotz's house was putting off prospective buyers. Disputes came thick and fast.

On July 23 last year Community Protection Warning Notices had been issued to both women banning them from harassing, trespassing or taking photographs of each other. On July 31 a security doorbell videoed Foxwell walking past and swinging her bag into Miss Lotz's head as she tended her front garden.

On the day of the fatal attack Foxwell was living with her new boyfriend Anthonie Vroon, a 36-year-old Dutchman. The pair had been removing garden panels adjoining the victim's garden to paint them.

Yet another row broke out with both women calling police. An officer attended but left soon after. At around 8pm Miss Lotz was filmed by Foxwell on her mobile as she moved an orange wheelie bin to the gap in the fence.

Miss Lotz then grabbed the phone and ran into her home pursued by her neighbour, who threw clay pots and a lawnmower against her windows. Foxwell went to her shed to collect the spade.

Miss Lotz's lodger Liam Graham told the jury how she then barged into the lounge. He recalled: 'She said, 'Where is she?' I said, 'Who?' She said, 'You know who.' I said: 'I don't know where she is.'

She was swinging the spade from side to side. She put the spade through a great big TV and smashed a laptop into a million pieces.'

Spotting Miss Lotz leaving the house she gave chase, catching up with her as she hammered at another neighbour's door, shouting: 'Help me, help me.'

Mr Graham said: 'I was screaming at her to stop. I tried to intervene once. She turned and said 'You best stay out of the way if you know what's good for you'.'

The end result? Multiple lives in ruins. And all for what? As Miss Lotz's friend said: 'What's so shocking is that a dispute over a fence could turn to murder. Who on earth would take an argument that far?' Foxwell is due to be sentenced on March 20.