Camden’s teachers’ union has criticised a “broken” Ofsted for not painting a fair picture of the borough’s schools – after an annual report revealed a chasm between the quality of its primaries and secondaries.

Pupils are more likely to attend a “good” or “outstanding” primary school in Camden than anywhere else in the country, according to Ofsted figures released on Thursday.

However, their chances plummet when they reach secondary school age, after Acland Burghley School in Tufnell Park and UCL Academy in Swiss Cottage were handed “requires improvement” ratings in the past 18 months.

Camden Teachers’ Association, the local branch of the National Union of Teachers (NUT), said that Ofsted’s inspection reports closely mirror exam results.

Consequently, they do not give “the whole narrative”, it said.

Andrew Baisley, secretary of Camden NUT, said: “The problem is that Ofsted is completely broken. I don’t think the profession places much store by what they have to say.”

He added: “People are obviously very proud when they achieve ‘outstanding’, it takes a phenomenal amount of work to do.

“But sometimes people feel unfairly treated, because Ofsted is forever changing its criteria.”

Inspectors found that 98 per cent of pupils attend a “good” or “outstanding” primary school in Camden, tying with North Tyneside for the highest percentage of top primaries in the country.

It is the second time in three years Camden’s primaries have been rated the best in England.

However, the borough dropped down to 48th in the country for its secondaries, with 84 per cent rated “good” or “outstanding”. It comes far below first-placed Haringey, where 100 per cent of secondaries are rated highly, and Barnet with 90 per cent.

Luca Salice, chairman of governors at Torriano Junior School and chairman of Camden Chairs and Governors Forum, said: “Camden has excellent schools but we want them to do even better.”

Camden Council leader, Cllr Sarah Hayward, said: “Camden’s unique social mix presents some challenges for our schools, and we know that factors like deprivation can impact on educational attainment.

“Despite this, our pupils are achieving excellent results.”

Cllr Angela Mason, cabinet member for children, added: “We are hopeful that the two schools which have had problems, we are turning them around. We aspire to be the best in the country all round.”

Cllr Mason also praised Camden’s “outstanding” GCSE results, after the Department of Education confirmed that 61 per cent of pupils achieved five A* to C grades, compared with 55 per cent nationally.

In line with almost every other local authority in the country, it is the lowest percentage of “good” GCSE grades in six years.

Mr Baisley said changes to exams brought in by former education secretary Michael Gove mean that grades “are not comparable” to previous years’ results.