28/09/2017 09:17 BST | Updated 28/09/2017 09:17 BST

The Countess Of Lucan Dies - But Britain's Biggest Mystery Remains Unsolved

It is difficult to imagine a sadder and more lonely life than that of the Countess of Lucan - found dead this week at the age of 80 after four decades of utter misery.

Lady Lucan will forever be defined by the greatest British mystery of the 20th Century. She was at the very epicentre of the Lord Lucan scandal, and though it happened over 40 years ago, it blighted her entire life.

And what a wretched life it was to become. For well over the last three decades, Lady Lucan was estranged from all three of her children. She turned into an embittered recluse who seemed not to have a single friend in the whole world, living in the very house where her crazy husband had lived and still surrounded by his pictures.

Lady Lucan will for ever be remembered for one thing and one thing only - the night in November 1974 when her estranged husband tried to kill her and instead ended up bludgeoning the nanny to death. Lord Lucan has never been seen or heard of since.

This single awful event came to define Lady Lucan. It didn't matter what else she did with her life, the only reason she was ever in the public eye was because of the botched murder of Sandra Rivett and the ongoing manhunt for her husband.

For me as a journalist, the extraordinary story of Lucan's disappearance had a compelling quality like no other. A few years ago, I wrote a book about the Lucan mystery - Lord Lucan: My Story - but always at the centre of the story had been this woman who remained a complete enigma.

That was until four months ago. In May, Lady Lucan finally broke cover to give her first TV interview. It was awful - and it was also utterly spellbinding. She wasn't just tough. She was as hard as flint. Along with the interview, she'd also written an autobiography, A Moment in Time, due to be published later this year and recently serialised in The Daily Mail.

What struck me about Lady Lucan's life was that, right from the get-go, her marriage was just hellish. It's hard to believe that things could have got any worse, but they most certainly did.

Veronica was a pub landlord's daughter who was brought up in Hampshire. She must have thought she'd lucked out when she started dating the rich, dashing Lord Lucan. They were married in the winter of 1963 and Lucan picking the church music. The irony is grim: they left the Holy Trinity Brompton to Beethoven's Ode to Joy.

The pair honeymooned on the Orient Express to Istanbul, spending most of their time bored and not talking to each other. They'd been given £200 worth of gambling chips as a wedding present by Lucan's so-called friend John Aspinall. Lucan decided to use the chips - and what happened next is just eye-popping.

He allegedly lost the £200 at that most banal of card games, Chemin de Fer - and then went on to lose a further £8,000 in the night. To give you some idea of how much he lost, a short while later Lucan he bought an entire house in London's Belgravia for £17,500.

Within two months of getting married, Lady Lucan's father-in-law had died and she had become a countess. She didn't cook, so they usually ate out. Most days they'd have lunch at Aspinall's Clermont Club. Their lifestyle sounds utterly vacuous and unbelievably boring. Lucan was at his most affectionate when he'd lost money.

At other times, she had to rescue Lucan out of the club before his winning streaks came to an end. Not that it made much odds: within a few years, Lucan had lost his entire fortune - now worth around £7 Million - to Aspinall and his stooges.

When they went on holiday to Switzerland or the Bahamas, Lucan still spent his entire time gambling. His wife would sometimes wake up at 4am to find her seedy husband still gambling away - surrounded by dead sandwiches, empty bottles and overflowing ashtrays.

She'd hoped that when he took his seat in the House of Lords, Lucan might start mixing with a nicer bunch of men. Unfortunately he didn't take to the place. Though Lady Lucan does recall seeing Lucan in the House of Lords and thinking that he was undoubtedly the most handsome man in the entire Chamber.

When she was pregnant for the second time in 1966, Lucan is said to have bought a large Doberman Pinscher, Otto. When she was lying in bed, Lucan would often urge the dog, "Jump on her!"

After three years of marriage, Lucan did his best to have his wife sectioned in a posh lunatic asylum. When that didn't work, he had doctors dose her up with a vast cocktail of drugs and sleeping pills. She was for ever short of breath, often losing her memory and her vision.

Her life then was a constant bout of pills, depression and visits to mental hospitals - and throughout it all, Lucan himself sailed on serene, moving out of the family home and still gambling like a maniac.

Since by now Lucan had lost all his money, Aspinall had kept him on as a house-player at the Clermont Club, where he'd get his meals and pin money and where he'd use his title to lure in more rich suckers.

At the time, Lady Lucan said she was on the verge of suicide, even locking the upstairs windows of her home so that she couldn't throw herself out.

Who knows how it might all have ended, but as it was Lord Lucan decided to take matters into his own hands. He tried to kill his wife and instead murdered poor Sandra Rivett.

That botched murder would come to define not just the Earl of Lucan and his wife, but also to a certain extent his son and heir George who recently became the 8th Earl of Lucan.

Though it all happened 40 years ago, it is still a mystery that captivates. Is it perhaps too fanciful to imagine that, at the age of 82, Lord Lucan is still alive, perhaps eking out his days in Africa, where he is currently digesting the news that finally, at long last, his wife is dead?