Dame Esther Rantzen has hailed the new “wonderful” assisted dying Bill but admitted she regrets that it would probably come in too late for her.

The broadcaster praised Kim Leadbeater for her commitment, compassion and courage in taking on the divisive issue, saying the MP’s late sister Jo Cox – who was murdered in 2016 – would be “incredibly proud”.

Dame Esther, who has terminal cancer and revealed in December that she had joined Dignitas due to the current law in England, said unless her current medication turns out to be “totally miraculous” and extends her life by a few years “there’s no way an assisted dying law can come into force in time for me”.

I understand that politics is the art of the possible, and having these narrow criteria makes it possible politically to get this reform through, which is so crucial

In a statement on Monday, she added: “But then I always knew that was not possible.”

Ms Leadbeater told the PA news agency that the first assisted death under her Terminally Ill Adults (End of Life) Bill if it was passed was likely to be two to three years away.

She recognised this is “heartbreaking in some respects” for those people and families for whom it will be too late.

Asked about Dame Esther, Ms Leadbeater told PA: “She is very poorly, but she’s such a fighter that she wants to make sure that people understand, as I’ve said, that the law as it stands – it will be too late for her, I’m fairly sure from what she’s said to me – but we’re fighting for the future of people who are terminally ill, to have a different choice, to have the autonomy, to have the control that Dame Esther will not have.”

The ChildLine founder, aged 84, also said she regrets that, if passed, the Bill would not apply to people with “chronic illnesses that can cause months of unbearable pain and distress”, but acknowledged there was a need to produce a proposal which might be supported by the majority.

Dame Esther said: “I understand that politics is the art of the possible, and having these narrow criteria makes it possible politically to get this reform through, which is so crucial.”

She added: “Congratulations Kim Leadbeater MP for your commitment, your compassion, your conscientious hard work, and your courage in choosing this as your Private Member’s Bill. Your sister Jo Cox would be incredibly proud of you.

“And thank you to all those who campaigned, and signed petitions, and shared their own tragic stories of the agonising deaths of those they loved, reliving so many painful memories.

“Thank you to all those in Parliament who support this vital reform.”

To those opposed, Dame Esther urged them to think of their loved ones – and themselves – facing an agonising death, as she reiterated the Bill “will give you the right to choose, not to shorten your own lives but to shorten your death”.

Looking forward to the debate on November 29, Dame Esther said she is “amazed and thrilled to have lived long enough” to witness what will be “such a landmark life and death moment”.

While not well enough to be there in person, she said she will “certainly be glued to my television with my fingers firmly crossed that the vote will go the way the vast majority of the public want, and have waited for so long”.

No number of safeguards can remove the threat of patient coercion, and citizens choosing assisted suicide because they feel like a burden or lack health, social care, or welfare support

Ms Leadbeater described the past few months as “harrowing” as she heard stories of people’s experiences with particularly difficult deaths.

“It’s been a really tough process if I’m honest, I’ve spent a huge amount of my time talking about death. And for most cases pretty horrible deaths,” she said.

But the MP said it has been “positive” in the sense it has opened up a conversation on death – a subject she said is not spoken about enough.

She added: “If we can facilitate that debate, whatever happens with the Bill, I think that’s got to be a good thing.”

Despite Ms Leadbeater describing her Bill as the “most robust piece of legislation in the world” with strict safeguards, others said it is not possible to guarantee against coercion.

The Christian Action Research and Education (Care) organisation said: “We fear the impact of assisted suicide on vulnerable and marginalised people in particular.

“No number of safeguards can remove the threat of patient coercion, and citizens choosing assisted suicide because they feel like a burden or lack health, social care, or welfare support.”