Britain’s youngest councillor - who dreamed of becoming Tory prime minister - was awaiting the results of heart tests when she died in her bed after spending the evening eating pizza and watching Downton Abbey, MailOnline has learnt.

Clarissa Slade, 21, a Conservative councillor in Devon and a third year Classics student at Winchester University, was found at lunchtime on Monday by her housemate who had been studying until the small hours.

The bright undergraduate was born with a heart defect and had recently been complaining of pain but a cardiologist told her that there was nothing to worry about.

Speaking exclusively to MailOnline, her father, Colin Slade, 64, who is a Devon county councillor for the Tories, said:

‘We’re devastated by the loss of our beautiful daughter. She had very much more to give. Her ambition long-term was to one day be Prime Minister. Who know what she might have achieved?

Clarissa Slade, Britain’s youngest Tory councillor, was awaiting the results of heart tests when she died in her bed after spending the evening eating pizza and watching Downton Abbey, Mail Online can reveal

Miss Slade, who was elected at the age of 18, was found by a housemate at her university accommodation in Winchester on Monday morning (pictured above with the Prime Minister last year)

The 21-year-old, who dreamed of becoming prime minister, had been for an endoscopy for a heart condition she was born with but was told by a cardiologist that there was nothing to worry about that she should 'go out and enjoy life', said her father Colin (above)

Tragic Clarissa, who dreamed of being a Tory Prime Minister and was the country's youngest councillor, pictured as a schoolgirl

Speaking exclusively to MailOnline, Mr Slade, who is a Devon county councillor for the Tories, said: ‘We’re devastated by the loss of our beautiful daughter. Her ambition long-term was to one day be Prime Minister. Who know what she might have achieved?'

‘We know that she did have a couple of small holes in her heart, but they had not been assessed as being of any great risk going forward.

‘She was told by the cardiologist to go out and enjoy life. So it is a complete shock and we don’t have any answers yet.’

Clarissa was elected as a district and town councillor at the age of 18 in Tiverton, Devon, where she was brought up.

The former private schoolgirl spent Saturday campaigning in Winchester ahead of the local elections and on Sunday undertook a shift at the local Wetherspoon’s pub before going home to her shared student house in the evening.

‘She sat up with her housemate watching Downton Abbey and eating pizza and went to bed about half-past one,’ Mr Slade said.

‘When they parted and went to bed, Clarissa said how much she was looking forward to coming home and we were supposed to be going to Sheffield this Easter for my son’s 40th birthday. She was really looking forward to that.

‘Her housemate found her in bed about lunchtime. You know what students are, her housemate had actually been up until about half-past-four in the morning doing some coursework or something.

‘She didn’t wake up until about 12 and then somehow realised that Clarissa hadn’t left the house, so she went into her room and found her and raised the alarm.

Clarissa was elected as a district and town councillor at the age of 18 in Tiverton in Devon where she was brought up. Pictured with Jacob Rees-Mogg in October 2017

The former private schoolgirl spent Saturday campaigning in Winchester ahead of the local elections and on Sunday undertook a shift at the local Wetherspoon’s pub before going home. Pictured with former Defence Secretary Michael Fallon (left) and William Hague (right)

Mr Slade said: 'She sat up with her housemate watching Downton Abbey and eating pizza and went to bed about half-past one.' Pictured with Boris Johnson

‘As far as we understand, she died in her sleep. We won’t know for sure for a while yet but that certainly appears to be the case.’

Her half-brother James, 39, and half-sister Trudy, 42, are ‘in bits’, Mr Slade added.

The last time that he and Clarissa’s mother, Elizabeth Slade, 66, saw their daughter was ‘two or three weeks ago’, her father revealed.

‘She was fine in herself,’ he said. ‘She had had one or two pains and she had had to go to a Hampshire hospital. They thought they’d better check, so they did do an endoscopy and they did take a biopsy. We haven’t been told the results of that, so it’s more questions than answers.’

Clarissa was due to travel by train back to Devon on Monday to attend a council meeting and when she did not reply to text messages from her parents, they contacted Hampshire police.

‘We were told [of her death] later that afternoon by an officer from a local station here in Devon,’ Mr Slade said. ‘What happened? We simply don’t know. We just don’t know.’

He added: ‘I have a timeline from the police but we have no medical findings as yet. There will be a post mortem. I’ve been advised by the coroner’s office that because of the Easter holiday, they might not actually have anything until next week.

'This is obviously very frustrating, because once you get over the initial shock the first question is: why?’

The last time that he and Clarissa’s mother, Elizabeth Slade, 66, saw their daughter was ‘two or three weeks ago’, her father revealed, as he described her siblings as 'in bits' over the news of her death

Clarissa was due to travel by train back to Devon on Monday to attend a council meeting and when she did not reply to text messages from her parents, they contacted Hampshire police. Pictured with her parents after being elected onto two local councils in May 2015

Post-mortem results are not expected until after Easter, much to the frustration of her parents

Clarissa was brought up in a Conservative family. Both her parents were Tory councillors and Mr Slade worked for CCHQ in the southwest from 2010 to 2013

Clarissa was brought up in a Conservative family. Both her parents were Tory councillors and Mr Slade worked for CCHQ in the southwest from 2010 to 2013.

‘She kind of followed in my footsteps,’ he said. ‘She professed herself to be very comfortable being a Conservative and she didn’t want to go anywhere else.

‘She had friends of other persuasions but she was very comfortable with being a Conservative and she became very active.

‘She went to party conference, she met a number of leading politicians, she was invited to 10 Downing Street when David Cameron was prime minister.

‘It was a great achievement to have become Britain’s youngest councillor at the time of her election.’

Her passion for politics was all the more remarkable considering that she suffered from Asperger syndrome, her father said.

‘She never tried to hide it or shy away from it,’ he said. ‘She was doing pretty well. There were certain things she found difficult but she found ways to overcome them.

‘She initially found any kind of social interaction very difficult and it took her a long time to make friendships at school. Then once she made friends they became very loyal friends.

‘She kind of threw herself into life, particularly getting involved in politics and campaigning and so on, as a way of overcoming some of those difficulties.’

Her passion for politics was all the more remarkable considering that she suffered from Asperger syndrome, her father said. ‘She never tried to hide it or shy away from it,’ he said. ‘She was doing pretty well'

The promising student, who was single at the time of her death, also had a great love of the mystery writer Agatha Christie

The promising student, who was single at the time of her death, also had a great love of the mystery writer Agatha Christie.

‘She loved Agatha Christie books and the spin-off TV series and things,’ her father said.

‘For her 21st birthday, we asked if she wanted a party and she said that she’d rather go to Greenway, Agatha Christie’s home in Devon. It’s a National Trust property.

‘So we went to have a day at Greenway and I bought her Agatha Christie’s autobiography as a birthday present, which she was thrilled with.’

Steve Brine, Conservative MP for Winchester, said: ‘Clarissa was a lovely girl who enjoyed campaigning with us and we enjoyed having her on the team. Our prayers are with her family at this sad time.’

George Marshall-James, the chair of Winchester Students' Conservative Society, who often went campaigning with Clarissa, said: ‘Clarissa had a wonderful personality that shone through all aspects of her life, from politics to her studies and to her programme on the university radio station. She was a pleasure to know and she will be deeply missed by us all.'

Russell Norton, a local Tory activist and fellow campaigner, added: ‘Clarissa brought fun, enthusiasm, dedication and energy to her campaigning over the past three years here in Winchester and Chandler’s Ford, and we will all miss her greatly.’