Sir David Nicholson has told MPs the suggestion he changed his opinion to fit the facts was “beyond response” during a heated discussion on the pay of senior health service managers.

At the Commons health committee hearing on public expenditure in the health service, the NHS England chief executive was asked how many individuals made redundant during the reforms were back working in the NHS.

Sir David said there were no such individuals working for NHS England “as far as he knew” but was unable to answer for other parts of the system.

Conservative MP Charlotte Leslie asked specifically about whether former NHS London chief executive Dame Ruth Carnall was doing paid work for the NHS after taking redundancy. Sir David responded that he understood she had been advising NHS organisations in Manchester on reconfiguration in an unpaid capacity.

However, the committee was informed that Dame Ruth had clarified on Twitter that she had not taken redundancy but worked her notice and was drawing her pension, alongside undertaking a mixture of paid and unpaid work.

Ms Leslie said “most people on most planets” would say it was “completely unacceptable” for Dame Ruth to be earning money from the NHS while drawing her pension.

Sir David said Dame Ruth was an “extraordinarily talented leader” and did not believe she had broken any rules.

However, Ms Leslie accused Sir David of having been reluctant to admit that she was being paid, and suggesting in his earlier comments it would have been inappropriate.

“The facts change and your attitude changes,” she said.

Given the opportunity to respond by committee chair Stephen Dorrell, Sir David said: “It’s beyond response.”

Earlier in the hearing Labour MP Barbara Keeley pressed Sir David repeatedly on whether he agreed with comments made by NHS England medical director Sir Bruce Keogh earlier in the day that senior managers deserved their high salaries.

Sir David said very senior managers pay had been reviewed by the government to ensure it was appropriate for the level of responsibility the roles involved. He suggested those at the top of arm’s length bodies had been subject to greater pay restraint than individuals leading foundation trusts or clinical commissioning groups.

Asked what kind of message these salaries sent to lower paid staff, Sir David said senior NHS managers were involved in “some of the biggest and most significant transformational change the NHS has ever seen”.

“We really do need really good, top drawer people to lead that… These are among the most complicated difficult jobs in the world: chief executive jobs of a scale managerially that very few of us would understand.”

Sir David was also asked about comments he made at the HSJ Commissioning Summit in September about competition rules getting in the way of reconfiguration. He said NHS England was “talking to Monitor” to find out if it was the way the law was being interpreted or the legislation itself. He said he would support using the Care Bill to make any amendments.

He added: “We have got competition lawyers all over the place which is causing enormous difficulty.”

Totnes MP Sarah Wollaston asked about Torbay Care Trust’s plans to vertically integrate with South Devon Foundation Trust which she said faced being “held up” by an Office of Fair trading. Sir David said he was discussing the case with Monitor.

“We will do everything we can to make that happen because it’s absolutely sensible,” he said.