The backers of the controversial medical innovation bill have insisted the legislation will not encourage ‘reckless experimentation’ with patients’ lives.

The team promoting the bill, tabled by Conservative peer Lord Saatchi to encourage medical innovation by reducing doctors' exposure to negligence actions, insists the majority of the 18,000 respondents to a consultation on change are in favour.

However legal and medical groups have expressed their concerns over the details of the legislation and have warned it is likely to confuse rather than clarify the legal position on doctors treating cancer patients.

A revised version of the bill will be introduced in the House of Lords on Thursday, with supporters hopeful it can return to the Commons by the autumn. A Department of Health consultation closed last month.

A briefing note for the revised bill admits that the draft version ‘lacked precision and clarity’ about the level of protection offered to medical professionals.

The new bill will include an obligation on doctors to register innovative interventions in order to enjoy the bill's protection. A doctor will not be able to proceed unless there is ‘general consensus’ supporting the proposed innovation from other medical experts, while the patient must also consent.

‘The new draft bill is clear and explicit – there can be no protection under the bill without following a clear and transparent process involving a panel of relevant experts and the responsible officer,' the briefing note says.

‘The bill team does not wish the bill to be used as a guise for reckless experimentation and thus the bill states that it may only be used in the best interests of the individual patient.’

Health secretary Jeremy Hunt has publicly backed the intentions of the bill, but groups such as Action Against Medical Accidents (AvMA) and the Association of Personal Injury Lawyers have reservations.

AvMA chief executive Peter Walsh has warned the bill is based on a ‘complete misunderstanding of how clinical negligence law works’. He added: ‘It is dangerous. It could lead to reckless treatment decisions by maverick doctors, and could deprive patients injured by clinical negligence of the justice they need and deserve.’