A second Cabinet minister has criticised Prince Charles over his claim that Britain's education system led to unrealistic ambitions.

Charles Clarke, the education secretary, had earlier said that such a claim was "old-fashioned and patronising".

"We can't all be born to be King but we can all have a position where we can really aspire for ourselves and for our families to do the very best they possibly can," he added.

But the Prince used a speech to tourism leaders last night to stand his ground.

He claimed that 12 years ago he had been ridiculed for having "fiendishly old-fashioned views" that tourism and architecture needed to be environmentally friendly.

John Reid, the health secretary, then filmed an interview to be broadcast on Channel 4 on Saturday, saying that his Cabinet colleague was "a much bigger Charles in many ways".

While on many issues, such as organic food and the environment, Prince Charles had been ahead of the game, "on this occasion I happen to think he is wrong", Reid said.

Downing Street refused to get involved in the spat.

"I know that Charles Clarke values his relationship with the Prince of Wales and enjoys discussions on education with him," a spokeswoman said.

"If people have a difference of views that doesn't mean they are showing disrespect."

Tim Collins, the shadow education secretary, said Clarke's comments were "unworthy" of a minister of the Crown.