The review of the policy says that if MPs vote for the policy, the number of people who choose assisted deaths could be 4,000 per year within the decade when the law goes into effect.

The estimate is part of an official impact assessment, and civil servants have debated MPs to inform whether MPs are allowed to die in England and Wales.

It said the initial numbers would be low but are expected to grow over time.

But even within 10 years of the start date of October 2029, the upper limit of only more than 4,500 assisted deaths per year is less than 1% of all deaths, the document said. The lower estimate is only over 1,000 people.

The impact assessment also provides a financial analysis of the costs and savings involved – this is not a document that involves moral or philosophical arguments about and against policies.

As the bill returns to the House of Commons later this month, it is a key vote that will determine whether the bill becomes a law expected to occur in mid-June.

NHS savings could range from £919,000 to £100.3 million in the first six months.

The figure includes unneeded costs for hospital care, primary and community care, hospice care, medications and other options to assist death.

By the time the system is in operation for ten years, savings may range from £5.84 million to £59.6 million.

But there will be costs. Within a decade, assisted dying services may exceed £10 million a year. Training costs in the first six months alone may exceed £11 million.

One assisted death may involve six health and nursing professionals working 32 hours.

It said this could detach employees from existing services, but the overall impact is uncertain.

Each group that will review the case, including lawyers, psychiatrists and social workers, costs £2,000 per day.

Overall, it says that it is impossible to calculate whether the cost exceeds savings and vice versa because of too much uncertainty.

The Ministry of Health and Social Care said the government is neutral on this issue. It said the document was intended to help ensure that any legislation passed through parliament is "feasible, effective and enforceable".

Labour MP Kim Leadbeater, who is behind the bill, said she thanked for the work done on the impact assessment.

She said she remained “strongly convinced that the overall impact of this long overdue reform is to make the end of life in England and Wales more compassionate and safer”.

But Baroness Tammi Grey-Thomson, a former Paralympic, House of Lords, opposes the dying assistant, said: “This assessment highlights how assisted death will put disability and other vulnerable groups at serious risk by providing the economic incentives for the already overburdened and underpaid NHS to facilitate treatment.