British Prime Minister Theresa May put herself on a collision course with her main opposition party Friday by announcing the reintroduction of grammar schools.

In what is her first major domestic speech since entering 10 Downing Street, May unveiled measures to allow for a radical expansion of what she described as "good school places".

May's move has invoked the fury of the main opposition Labour Party who banished grammar schools on the basis they separated pupils at the age of 11 into two groups, one heading to an elite grammar school education that offered a better chance of university places and a profession. The majority went to secondary schools, most pupils destined for blue collar trades.

Labour scrapped the two tier system and instead introduced comprehensive schools for all students aged 11 and above.

Tony Blair, in 1998, a year after becoming Labour prime minister, brought in the School Standards and Framework Act which banned the establishment of any new grammar schools, only allowing those still existing to continue.

There are only 163 grammar schools in England compared to around 3,000 state comprehensive schools where pupils of all abilities and aptitudes are taught together.

A dual education system, viewed by Labour as elitist, is seen as one of the key differences between the two big political parties.

In her speech Friday afternoon May outlined a four-point plan of action to improve education, including a reintroduction of grammar schools.

But she insisted it would not be a return to the grammar schools of the 1950s with their life-changing tests for admission or rejection at the age of 11.

She said: "The debate over selective schools has raged for years."

"Frankly, it is completely illogical to make it illegal to open good new schools. I want to relax the restrictions that stop selective schools from expanding," said May.

"It is not a proposal to go back to the 1950s but to look to the future, and that future I believe is an exciting one," she continued.

"It is a future in which every child should have access to a good school place. And a future in which Britain's education system shifts decisively to support ordinary working class families," she added.

Labour's Shadow Education Secretary Angela Rayner, said: "Theresa May talks about standing up for the majority but her actions reveal the opposite: working for the few at the expense of the many."

Labour's attack continued with May's proposed reforms condemned by Labour shadow minister Jonathan Ashworth.

He said: "It's utterly ludicrous for Theresa May to stand up and talk about creating a 'great meritocracy' and then in the next breathe announce a return to grammar schools."

"We're today calling on the Prime Minister to come to Parliament on Monday and explain why, when these policies weren't even in the Conservative Manifesto, she is now set to press ahead with a policy which is bad for the majority of our children. We will be opposing this regressive policy every step of the way," he said.