Mr Hurst longed to join his wife, Jean, who died three years ago

Gordon Hurst, of Hitchin, Hertfordshire, who had Parkinson's Disease, was given barbiturates at the Dignitas clinic in Zurich.

Relatives found out about his death from letters he had arranged to be sent to them after his death.

His family have been told no offence has been committed under British law.

I think what has happened is horrific, it has got to be wrong Former daughter-in-law, Lesley Miller

His former daughter-in-law, Lesley Miller, 44, from Letchworth, was so concerned she reported the matter to Hertfordshire Police.

She wants the Swiss authorities to close down the controversial clinic which is run by a charity.

"I think what has happened is horrific, it has got to be wrong," she said.

"It's scary to think that someone can jump on a plane at Luton Airport with their medical notes and get a flight out to Zurich where someone from Dignitas is waiting to meet them," she said

Mrs Miller said Mr Hurst deeply missed his wife of more than 50 years, Jean, who died three years ago.

Dear Chris, As you are reading this letter, I will have passed away and joined my dear wife Jean, your grandmother Mr Hurst's letter to his grandson

Mrs Miller was married to Mr Hurst's late son, Trevor, but remarried after being widowed.

Her son Christopher, 17, who had remained very close to his grandfather, received a letter after his death which read: "Dear Chris, As you are reading this letter, I will have passed away and joined my dear wife Jean, your grandmother."

The letter finished by saying: "Be happy for me because now I am free of all pain... "

Mrs Miller said: "I know this is what Gordon wanted, but I don't think Dignitas have helped him. To me life is so precious.

"Gordon was a wonderful, kind caring and dignified man, I think he deserved better. How can it be dignified to die in a flat in a far away place away from people that love you?

'Vulnerable people'

"Dignitas are dealing with very vulnerable people. Did they try to talk to him first? Was there any counselling?

"To them he was a stranger - they didn't know him or love him like his family."

She said her son has been left traumatised by what had happened.