It was also his first political speech since his disclosure last month that he had "homosexual experiences" as a young man.

But he has come in for criticism from fellow former Tory minister Lord Tebbit who has accused Mr Portillo of not being totally honest over the revelations.

Lord Tebbit told the BBC: "He owned up to a homosexual phase when he was not much more than a schoolboy and I am told that sort of thing is not uncommon amongst schoolboys.

"The truth of the matter is something different. What worries me about that is that he was not completely honest."

Lord Tebbit: Question marks over Portillo

The former employment minister said the "affair" was not a matter of concern, but added: "What is a matter of great concern is that he should have thought to mislead people."

He also said that in his opinion the revelations had damaged Mr Portillo.

"I think it has damaged him. You see, it leaves us wondering now what sort of man Portillo is.

"Some of us were worried anyway by the fact that after the general election he seemed to change from being the hard-right, tough macho secretary of state for defence wearing the SAS badge, almost, to the soft-focus guy we saw subsequently."

Mr Portillo's speech itself was low key and confined to education.

The intention was to minimise its potential interpretation as a leadership challenge to Tory leader William Hague.

Media commentator Matther Parris: "Portillo should tow the party line for a bit"

In his speech Mr Portillo called for education to prepare children for more than just a job in a materialistic and selfish society.

He also warned that if children missed out on education, they not only missed out on job opportunities but also on "enjoyment and self-fulfilment".

"There is much more to life than making money and collecting consumer durables," he said.

"There is the whole world of imagination. People need to be able to dream. Education is part of learning to be a human being."

Michael Portillo with words of support for William Hague

In his speech to the meeting at Blackpool's Winter Gardens, Mr Portillo added that there was room for more private sector involvement in education.

"Our last government did not exhaust the limits of privatisation or of partnerships between the private and public sectors. Not at all.