Thousands of patients facing long waits for non-urgent, diagnostic scans are to be offered the choice of faster treatment at an alternative hospital.
The scheme aims to cut scan waiting lists
The scheme will begin in November, and will use both spare NHS capacity and private contractors.
Initially it will be offered to patients waiting longer than 20 weeks for a MRI or CT scan.
By April 2006 it will be extended to patients waiting longer than 16 weeks for most imaging scans.
Under the new scheme, the maximum waiting time for a scan should fall to 20 weeks.
But doctors have expressed concerns about funds being diverted from the NHS to the private sector.
Announcing the scheme, Health Secretary Patricia Hewitt admitted that many patients were caught in a 'bottleneck' of waiting for a scan or other diagnostic service, before they are referred for an operation.
She said: "We have already made it clear that by 2008 nobody will wait longer than 18 weeks from GP referral to their treatment in hospital.
"Speedier access to diagnostic tests is an essential part of achieving that.
"Whilst we build this capacity, I want to make sure that no patient has to wait longer than necessary for their scan if there is somewhere else in the NHS or independent sector that can provide it more quickly."
Ms Hewitt said the most serious cases, such as where a GP suspects cancer, are already fast-tracked for diagnostic tests.
"However, those patients waiting for less urgent scans should still get them as soon as the NHS can provide."
Dr Paul Miller, chairman of the British Medical Association's consultants committee, expressed concern at the involvement of private sector units.
"We think the NHS can do more for the money. Generally, we know that private providers have been costing more than the NHS.
"Very broadly the private providers have been being funded at 10-15% more than the NHS when they have been doing things like cataract operations and hip operations.
Dr Miller also feared that the private sector would be able to cherry-pick straightforward cases.
"We know that there are NHS scanners standing unused because of lack of funding to run them.
"We should concentrate our funding on NHS scanners first of all before diverting funds away to private sector providers.
"There are many trusts around the country that have got really severe financial problems, and if they lose a block of funding to a private sector provider that is only going to make the situation worse."