Education secretary says 'inflated' GCSE figures were used in past to tell pupils they could go to university or get skilled work

The education secretary, Michael Gove, has urged politicians to stop "lying to children" about their life chances and allowing inflated exam grades that he compared to Soviet tractor production propaganda.

"For years, ministers in previous governments looked at the way more and more people were getting GCSEs and they congratulated themselves, like Soviet economics ministers on the growth in statistics," Gove told a US summit on education reform on Thursday night.

Slipping into a mock Russian accent and syntax, Gove said: "Look in Russia, thousands more get GCSEs. Surely now we are education powerhouse?"

Instead, he told the audience in Boston, "the truth is that we were lying to children" by telling them they would be able to go to university or find skilled work.

"Employers said: 'You have a piece of paper that says it, you're qualified in English and mathematics. But you can't write a business letter, you can't do basic arithmetic required to work in this store or on this shop floor.'

"One of the things I have done as education secretary is to reverse that tide of inflating exam statistics and, in effect, devaluing what young people gained. I think there's no crime greater than lying to children – and that's why we need to tell them the truth."

Gove was the after-dinner speaker at the annual conference of the Foundation for Excellence in Education, a charity founded by the former Florida governor and potential 2016 US presidential candidate Jeb Bush, who addressed the conference earlier in the day.

Gove said teaching unions on both sides of the Atlantic were thwarting reform. He was speaking on the day that the two biggest teaching unions in England staged a one-day strike in parts of the country, closing hundreds of schools. "One of the things I would say to union leaders is: why are you putting the interests of adults ahead of the needs of children?"

Quoting liberally from the speeches of Martin Luther King, Gove upbraided his American audience for their country's income inequality and the effect it had on the children of the poor.

During the last 20 years in England, social mobility had gone backwards, Gove said. "It's a tragedy for me that in America income inequality has [also] grown, and that despite the efforts of so many it's still the case that if you are a child of colour you are half as likely to graduate from high school as a white child in this country.

"One hundred and fifty years after the Gettysburg address, 50 years after Martin Luther King's speech 'I have a dream', it's still the case that America and Britain are houses divided by inequality and lack of opportunity."

The US and the UK were divided internally by a "common evil" of inequality, Gove said. "Both our countries have great educational institutions of which we can be proud … but in both our countries access to those great educational institutions, those universities and schools, is rationed and restricted, increasingly, to those who live in upscale neighbourhoods, have parents who have access to connections, and are supported by stable families.

"Those children who were unfortunate enough to grow up in poverty, without a stable family background, without access to those connections, find it increasingly difficult to benefit from education."

The solution, Gove said, was for the victims of income inequality to be "placed in a great school with a great teacher. There really is no limit to what those children can achieve. But there are millions of children growing up in both our countries who will not have that chance."

Gove defended his decision to introduce more testing for pupils by drawing an analogy between two airlines. "Imagine that you had a choice not of schools, but of airlines. There is Test Airlines, very rigorous, and there is Warm and Fuzzy Airlines. What's the difference between the two? In Test Airlines they actually insist that the pilots have passed a test so that they can fly a plane. How old-fashioned can you get?

"At Warm and Fuzzy Airlines, they don't bother with these tests to see if pilots can fly. They just concentrate on all of the pilots giving the customers a warm and fuzzy feeling as soon as they get on board. Which would you fly with?"