Lady Lucan killed herself by taking a cocktail of alcohol and barbiturates after diagnosing herself with Parkinson's disease, an inquest heard today.

The 80-year-old, who was also known as Veronica, the Dowager Countess of Lucan, was found by police after being reported missing by a worried friend after not turning up for her regular walk.

Police smashed a window to break into her two-storey terraced townhouse in London's Belgravia last September.

The inquest was told Lady Lucan feared she had developed Parkinson's after she noticed a tremor in her right hand.

But the coroner said there was no formal diagnosis and an examination of her brain came back with 'normal' results.

However, Lady Lucan had also lost her sense of smell, felt tired, anxious and suffered from insomnia, as well as becoming forgetful.

She was one of the last people to see Lord Lucan - the 7th Earl John Bingham - alive before he became the most famous fugitive in the world.

He is alleged to have killed family nanny Sandra Rivett after mistaking her for his estranged wife during a bitter custody battle over their three children in 1974.

 The inquest heard Lady Lucan's friend David Davies was worried about her after she had not been seen for two days and missed their regular meeting at St James' Park. 

He went to Belgravia police station concerned she had killed herself, as the pair had discussed assisted suicide if they had a terminal illness or a degenerative disease.

Lady Lucan, who was born in Uckfield, East Sussex, had visited an Exit meeting on assisted suicide with Mr Davis the year before and also complained of money woes.

 Westminster Coroner's Court heard today she wrote in her diary about how to commit suicide if she became frail and had books on assisted dying.

A pathologist concluded she died from respiratory failure caused by a lethal dose of drugs and alcohol poisoning.

In one diary entry on August 5 last year, about six weeks before her death, she listed potential suicide items copied from four suicide books found in her house. 

An entry just weeks before she died detailed her suspected symptoms, but she had not been diagnosed by a doctor, the hearing was told. In a written statement David Davies, who had known her for two years, said: 'There was nothing in her behaviour to suggest anything was wrong.

'Although she thought she had the onset of Parkinson's and had a tremor in her right hand and was worried she'd lost her sense of smell.

'We went to an Exit lecture on how to help people with a terminal illness end their lives peacefully and Dignitas was mentioned.

'She gave the impression she was hard up and had to watch every penny and complained about interest rates going up. We both discussed how to end our lives but only if we developed a degenerative or terminal illness or became reliant on other people.

'But there was nothing to suggest she was considering this and she seemed cheerful the last time I saw her.'

The court heard Lady Lucan had gone through her autobiography's final edit a month before she died, with publisher Pamela McCleave. She had hoped it would come out before Christmas. 

It was revealed after Lady Lucan's death that she had asked her publisher to remove two references about her close relatives because she 'didn't want to upset them'.

Coroner Dr Fiona Wilcox recorded a verdict of suicide. She said: 'It's clear that Veronica Mary Lucan has for some time been considering how she could, if she was to take her own life.

'She attended a seminar in relation to this and she had four books and notes recovered from the scene and hand written notes which appear to be taken from the books. 

'It's clear from her diary entries of July, August, September she considered she suffered from Parkinson's disease, but there is no formal diagnosis and examination of her brain was normal.

'She had met with a publisher and I note she got up from the floor in a sprightly way, although she had seemed down. 

'There's no evidence of suffering from a mental illness, although she had complained of anxiety and insomnia, which medication had been prescribed.

'Evidence from her diary seemed to suggest she had concerns she was suffering from Parkinson's disease in the weeks and months leading up to her death. She had also selected her final photographs and final edit of her book.

'This was a lady of a regular routine and regularly met with friends on a daily basis in St James' Park to have lunch and go to the library. 

'Her friend David Davies became very concerned when he hadn't met her and in the park and went to the police station to report her missing.

'He was insistent at the time he thought she had taken her own life because she had knowledge of methods of suicide. But that said there was nothing to suggest any change in mood in her leading up to this.

'Her lifeless body was found wearing a blue dressing gown, slippers, with a small graze on her forehead.

'The pathologist gave a cause of death due to respiratory failure. This was supported by the congestion of the lungs, as well as barbiturates and alcohol poisoning.

'The level of barbiturates was above the normal therapeutic range and approached a fatal concentration, the effects of which would have been exacerbated by alcohol.

'It's clear there was nothing to suggest any third party involvement or forced entry or disturbance or disruption. When I consider all the evidence there's evidence of intention with hand written notes detailing concerns about her health. 

'Although there is no suicide note there are diary entries in which she details these thoughts. I'm entirely satisfied that suicide is the final conclusion.'

After the hearing her daughter Camilla Bingham, declined to comment.

Read more on dailymail.co.uk.