A health board which manipulated waiting time figures and missed targets has unveiled a £37 million recovery plan to redeem its reputation and bring its performance into line.

NHS Lothian was censured by public spending watchdog Audit Scotland for falsifying waiting times figures in 2011, and pressurising staff to manipulate numbers to meet shorter waiting guarantees.

The health board today recognised that it "is not delivering" for patients and has pledged to fulfil its statutory guarantee that no eligible outpatient will wait longer than 12 weeks by the end of the year.

The health board would like to meet its obligations sooner than December but this would require more extensive use of the private sector than managers would like, according to director of scheduled care Jim Crombie.

He said: "This strategy is a real and tangible roadmap for our future. It sets out our commitments to patients for the years ahead and explains how we plan to re-shape our services to provide more effective, patient-centred care.

"This strategy will see both new resources being brought into play but also redesign of existing clinical models to maximise effectiveness and efficiency.

"I have deliberately said that NHS Lothian is not delivering. Patients are waiting beyond the waiting time standards agreed with the Government and set out by parliament.

"This is not limited to areas of high complexity, but is occurring in some instances where capacity for these patients could be available by improving efficiency and productivity. This position must be recovered. I am keen not to only focus on the mechanics of waiting times but on the provision of quality and safety of our patients.

"We are still reliant on the private sector at this time, but over the next period that will be reduced as our in-house capacity and infrastructure grows."

Tim Davison, chief executive at NHS Lothian, said: "Our approach is about making sure we can deliver our targets safely. It will take time to increase capacity, infrastructure and staff but now we can at least be sure that we have a clearer plan that will deliver for the future."

Last month, NHS Scotland chief executive Paul Gray accepted criticism of the so-called waiting time guarantee, which was described as "a farce" by the convener of Holyrood's Public Audit Committee.

The Patients Right Act 2012 offers a treatment time "guarantee" of 12 weeks but no health board has met the target to date.

NHS Scotland performance director John Connaghan told the committee that there is no guarantee that it will be met in the immediate future.