The benefits of enabling patients to choose consultant-led teams is based on “limited” evidence, the Department of Health has admitted.

The DH announced on Tuesday that patients would be offered the choice of a named consultant-led team, where “clinically appropriate”, for their first outpatient appointment from April 2012. This is 12 months later than originally intended.

A statement said the roll out was “in line with what patients want”. It highlighted a DH commissioner survey that found 77 per cent of respondents wanted a choice over which hospital consultant was in charge of their care.

A DH impact assessment says evidence on implementing the policy is “limited” but “suggests” it will be “affordable”. It puts the “best estimate” for the net benefit at £50m over the next five years, with costs of £71.4m and benefits of £121.4m.

The benefits in short-term improvements in outcomes amounted to £110.2m and those in reduced lengths of stay hit £11.2m. But the paper says the “figures for the benefits are based on a single paper and therefore cannot be considered to be more than an illustration of the scale of likely benefits”.

Costs included £8.4m on GP consultation time, £4.7m on updating contracts and £3m on provideres maintaining new consultant team profiles on NHS Choices.

However, the paper acknowledges that other cost areas have not been quantified, including more patients choosing well known providers, often in expensive parts of the country.

It notes: “Information about different services is not currently available routinely at the level of named consultant-led team. To provide this information could cost money, although how much, or on whom they would fall, is unclear.”

Guidance on implementing the policy, also published on Tuesday, says commissioners and providers will need to decide exactly what information to provide – but it steers them towards waiting times.

Homerton University Hospital Foundation Trust medical director John Coakley said waiting times data was “not necessarily an indicator of quality”. He said: “One of the worst surgeons I have ever known had very short waits.”

Although he said the policy was a “step in the right direction”, he highlighted “potentially complex definitional problems”. “We don’t have orthopaedic surgeons now - we have paediatric, knee, hip, back and other sub specialties of orthopaedics,” he said.

Heart of England Foundation Trust chief executive and former hospital doctor Mark Newbold said there would be “pressure to get information out there” on new consultant-led teams, otherwise there was a “potential to skew [referrals] towards existing teams”.