I am replying to your article, Stats man quit over NHS 'lies' (Oxford Mail, May 3).

We have never deliberately manipulated or falsified our waiting lists to make our performance look better than it is.

Some years ago, we identified a number of weaknesses in our data collection systems, which meant that some patients were not immediately included in the waiting list.

This had no impact on the length of time patients had to wait or on the way our performance was assessed, as this has always been calculated from the date from which a decision to treat was made, not the point at which the patient's details were recorded on the system.

Despite this, we wanted to tackle the delay in recording the data and have implemented an action plan to rectify this.

Leonard Porter, who left our employment more than a year ago, raised concerns with the Audit Commission and the NHS Counter Fraud Security Management Service.

Both independent bodies reviewed our data collection systems and found no evidence of deliberate manipulation of the waiting list figures.

The Audit Commission report and their findings are publicly available.

Thames Valley Health Authority has also stated its confidence in the way in which we manage our waiting lists and are satisfied with the findings of both reports.

Mr Porter has made a number of allegations about the trust to independent bodies, none of which has been upheld.

We have offered Mr Porter meetings with senior staff to discuss these reports and he has chosen not to accept.

We take any concerns about the way in which we collect data extremely seriously and would view the deliberate manipulation of waiting list figures by any member of staff as a major disciplinary issue. Andrew Stevens, Director of Planning and Information, Oxford Radcliffe Hospitals NHS Trust