Trusts are currently only treating 35 per cent of patients within the 18-week target, the Department of Health has said.

The NHS is working to a milestone to have 85 per cent of patients being treated by 18 weeks by March 2008, and all patients dealt with within that time by the end of 2008.

The figure was released as part of a DoH 'baseline exercise' to see how long both admitted and non-admitted patients have been waiting from referral to treatment.

The work is intended to find hold-ups in the system, but does not identify what could be causing them.

Health minister Andy Burnham admitted that meeting the target was going to be challenging: 'This is the completion of the journey on waiting times that we began in 1998. This is not a top-down approach but relies on local enthusiasm and momentum,' he said.

Included in the exercise are breakdowns by strategic health authority and specialty, although tertiary treatments have been excluded.

Most specialties are treating 30-50 per cent of patients within 18 weeks, but trauma and orthopaedics remain problematic; each has less than one in five patients being seen within 18 weeks.

All specialties also still have some patients who are waiting for longer than 52 or 104 weeks.

Almost a quarter (23 per cent) of all trauma and orthopaedic patients are currently waiting 52-104 weeks.

Mr Burnham added that linking the target to choice was going to be critical. 'This is a complement to the aim of offering full choice across the NHS by 2008,' he said.

National director for 18 weeks Philippa Robinson said 37 clinical pathways based on meeting the target would be published by the end of the month.

Guidance on how to deal with patients who choose to wait longer is also expected.