Dame Esther Rantzen has been forced to pull out of a Westminster debate on assisted dying because she is too ill.

The campaigner and broadcaster, 83, who has said she is considering travelling to Switzerland for an assisted death, had been expected to attend the event next Monday. She said she will be watching closely.

In a statement Dame Esther said: "While, sadly, my health issues (I have stage four lung cancer) prevent me from attending it myself, I will be watching the debate closely as it affects my own decision to go to Dignitas in Zurich if necessary, to protect my family from witnessing a painful death."

MPs are to debate assisted dying for the first time in almost two years after a petition backed by Dame Esther secured more than 200,000 signatures. She said: "The current law means my family could be prosecuted for supporting me if I go to Switzerland. This is not right, it is not ethical and, as it is my life I, like the majority of the public, believe it should be my choice."

On Tuesday politicians on the Isle of Man paved the way for it to become the first part of the UK to legalise assisted dying. Members of the island's House of Keys formally accepted a landmark report on an Assisted Dying Bill.

It paves the way for a historic vote in the coming weeks. Dr Alex Allinson, the doctor and Member of the House of Keys behind the Bill, said: "This is not a race. What we need to do is get the right legislation for the people of the Isle of Man."

Politicians on the island will discuss the report next month.

It comes after legislation to introduce assisted dying for terminally ill people in Scotland was published last month.

Scottish Parliament member (MSP) Liam McArthur said he was "confident" his colleagues would back the legislation in a vote, adding "robust safeguards" are included in the Bill.

But opponents of the legislation fear the lives of people who are ill or disabled would be "devalued". The Bishop of Paisley, John Keenan called it a "dangerous idea".

It is set to go to a vote in Holyrood later this year, amid growing pressure on the UK Government to legalise assisted dying.