The new Children, Schools and Families Secretary set himself on a collision course with the teaching establishment yesterday by pledging that national testing and school league tables were here to stay.

Despite growing pressure from the Government’s own examinations regulator and the majority of the teaching profession about overtesting in schools, Ed Balls said that “testing and the publication of results” were the only way to ensure accountability.

“It enables us to be able to see as policymakers what is working, who is not performing well and, in the extremes, being able to tackle poor performance,” he told The Times.

It was necessary also, he said, to help parents to judge the performance of their child’s school.

Mr Balls’s comments will disappoint the main teaching unions, as well as the professional body, the General Teaching Council. All complain that, far from raising standards, overtesting encourages a narrow curriculum, alienating students from learning and increasing their anxiety.

Children in England typically sit 70 tests and exams in their school careers and are the most tested in the world. Despite this, Britain is near the bottom of international league tables for the number of students leaving school with valuable qualifications.

Critics of testing include Ken Boston, head of the examinations regulator, the Qualifications and Curriculum Authority, who has argued that national tests for children aged 7, 11 and 14 should be replaced by the random testing of a sample of pupils and teacher assessments.

Mr Balls’s opposition to this approach will also distance the Government from the Conservative Party, which has promised “fewer but tougher” tests and the dropping of Key Stage 3 tests at 14.

In his first newspaper interview since he was appointed three weeks ago, Mr Balls also attacked Tory support for more streaming and the promise made by the Conservative leader, David Cameron, for a “grammar stream” in every comprehensive.

Mr Balls stopped short of banning streaming, which involves separating children into groups according to overall ability and teaching them in the same class for all subjects, arguing that individual head teachers know what works best in their own schools. But he emphasised that it was “backward-looking and divisive”, imposing an arbitrary judgment on children’s intelligence and ignoring individual talents.

He said that he would rather see a greater use of setting, where children are separated into ability groups for individual subjects. “I do not find anybody sensible advocating streaming in schools. As somebody who went through streaming myself through secondary school I saw how deeply socially divisive it was,” he said.

Mr Balls said that he would be making a series of impromptu visits to schools to spend time with teachers and pupils, who would not be informed who he was.

He made his first such visit on Monday, when he spent the day at Banbury School in Oxfordshire, having informed only the head, the deputy and two senior staff members of his intention to visit. He arrived on foot, having asked his driver to drop him some distance from the school and was introduced to teachers and pupils as “a visitor”.

He said that there was an old-fashioned view that you either focused on the welfare of the child or drove up standards in the classroom. His visit to Banbury had shown him that this was a false choice. “You can only drive up standards if you are actually focusing on the whole child, tracking their learning on an individual basis, but also knowing that if they aren’t ready to learn because they are not sleeping or have difficulties at home, it’s not possible for them to do well,” he said.

He was determined to tackle the “achievement gap” in society, emphasising the importance of closer cooperation between education, health and social care services for children.

“There are children in the same borough, on the same streets sometimes, and even going to the same schools, who have radically different experiences, shaped by family income and family environment, by poor health. The scandal is not England v Sweden, but Blackbird Leys v Headington. It’s Harehills v Roundhay. It is North Kensington v South Kensington,” he said.

Mr Balls said that more than 400 city academies could be set up, but insisted that they should become part of the “mainstream” and work more closely with nearby schools.

The man who has spent most of his political life advising or working for Gordon Brown admitted that he felt “a bit liberated” at being outside the Treasury at last and declared himself ready to argue hard with his former colleagues for cash.

Acknowledging that plans for a more flexible national curriculum would place a heavy burden on teachers and head teachers, he said that he would welcome the appointment of head teachers from outside the teaching profession.

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