The broadcaster tells the BBC she will consider assisted dying if her lung cancer treatment fails.
Dame Esther Rantzen says a free vote on assisted dying would be top of the agenda if she were PM for a day.
“I think it’s important that the law catches up with what the country wants,” the veteran broadcaster told Radio 4’s Today programme.
Earlier this year, the 83-year-old announced she had been diagnosed with stage four lung cancer.
Dame Esther told the BBC she is currently undergoing a “miracle” treatment to combat the disease.
However, if her next scan shows the medication is not working “I might buzz off to Zurich”, where assisted dying is legal and she has joined the Dignitas clinic, she said.
She said this decision could be driven in part by her wish that her family’s “last memories of me” are not “painful because if you watch someone you love having a bad death, that memory obliterates all the happy times”.
However, if she did travel to Dignitas, that would put “my family and friends in a difficult position because they would want to go with me”, Dame Esther told the programme, “and that means that the police might prosecute them”.
Under the law in England and Wales, anyone assisting someone to die or accompanying them abroad to do so can be sentenced to up to 14 years in prison.
“We’ve got to do something. At the moment, it’s not really working, is it?” Dame Esther said.
Speaking about assisted dying, Dame Esther said people are “given the choice over so many other things, medical and otherwise. Why should you not be given the choice about how you want to go and when you want to go?…
“I get all the arguments about… not wanting to be a burden and pressure being applied and all that. But… you can come to the wrong conclusion.
“If you just base everything on the worst case scenario, you’ve got to have a look at the advantages as well.”
Almost a year on from her diagnosis, Dame Esther told Today she had not expected to live with cancer for so long.
“I thought I’d fall off my perch within a couple of months, if not weeks. I certainly didn’t think I’d make my birthday in June, which I did, and I definitely didn’t think I’d make this Christmas, which I am. It appears, although anything can happen,” she said.
At the time, Dame Esther said the news had prompted her to express “profound thanks to everyone who has made my life so joyful”.
By May, she announced her lung cancer was in stage four, the most advanced stage, which means the cancer has spread beyond the lungs or from one lung to the other.
Dame Esther enjoyed a successful TV presenting career which included hosting BBC consumer show That’s Life! for 21 years.
She is also known for launching ChildLine in 1986, the first national helpline for children in danger or distress.
In 2013, she launched the Silver Line, a charity to help elderly people suffering from isolation and loneliness.