He was the leader of the biggest teacher union in Washington DC fighting reforms to how teachers were paid until he had what he described as an “ah ha moment”.

George Parker, former president of the Teacher Union in the US capital, told the Conservative Party Conference today of his Damascene moment that paved the way for performance- related pay to be rolled out across the school district.

The American is in the country to extol the benefits of the controversial pay reforms and he drew a standing ovation from the Tory faithful.

His comments came as tens of thousands of teachers across England were on strike today - in part in protest againt the introduction of performance-related pay.

Mr Parker said he had his epiphany after speaking at a school where he told a class of children that his job as a union leader was to put good teachers in their school.

“When I finished speaking a little girl came up to me a have me a great big hug,” Parker said. “I asked her why she did it and she said it as because I cared about them.”

The former maths teacher said he knew that was not true, however, because he had spent $10,000 through arbitration on getting a bad teacher back into their class.

“It was then that I had my ah ha moment and I knew that what I had told that little girl was not true,” he said. “I couldn’t say that I cared for them when I had just negotiated for a teacher I knew was bad to be allowed back into the classroom.”

Mr Parker ushered in the reforms put forward by the controversial chancellor of Washington DC’s schools at the time, Michelle Rhee, which linked teachers’ salaries to their performance in the classroom.

Teachers in the school district received a 21 per cent pay increase over five years in return for the changes.

The former unionist now works alongside Ms Rhee at her not for profit organisation Students First.