Government officials and advisers sought to apply "improper" pressure over independent reports on service delivery, the outgoing controller of the audit commission, Sir Andrew Foster, has claimed.

In an interview with the Times, which will undermine government attempts to avoid further accusations of spin, Sir Andrew suggested that ministers' desire to score "short-term hits" undermined efforts to achieve long-term improvements in health and education.

Sir Andrew alleged that the pressure was applied in the run-up to publication of last year's comprehensive performance assessment of local authorities. Efforts were made, he claimed, to force last-minute changes to the documents - thought to have included demands that councils with failing schools be marked down.

Sir Andrew described how "quite serious pressure was being brought to bear", and said: "I certainly took the view that this was improper."

"The criteria for the assessment had been agreed with ministers," he continued. "The situation only resolved itself when I said I would report this and put it into the public domain."

Sir Andrew also detailed how the commission was forced to delay a report criticising the value for money of privately financed new schools because ministers "were unhappy with the message".

And he claims that the health department tried to minimise the impact of a commission report on accident and emergency waiting times because the health secretary, Alan Milburn, was "very unhappy because it did not give a positive image". Sir Andrew added that the government wrongly claimed the report was based on old information.

But Sir Andrew said that Labour was not alone in finding the commission "unwelcome visitors at their table". The same was true of the last Conservative government, he claimed.

Michael Howard, then home secretary, was apparently infuriated when the commission described the youth justice system as a "shambolic mess", and went so far as to question its right to express such criticism.

Sir Andrew believes that some of the friction between the commission and the government is due to its expanded role - it has taken on responsibility for measuring performance and assessing whether targets have been met. "It is understandable for ministers to become increasingly sensitive," he said, "this is very challenging for them".

Sir Andrew, who is due to retire after 10 years at the commission, predicts more tension with government. "The longer any government is in power, the number of issues we will report on will grow," he stated. "The heat in this particular kitchen will get hotter."