Exams protest at education secretary's office in Codsall

Students wanted to protest about the "significant level of disappointment and frustration they feel", head teacher Alun Harding said

Dozens of students protesting over the A-level results system have marched on the constituency office of Education Secretary Gavin Williamson.

About 30 students marched from Codsall Community School in Staffordshire to the South Staffordshire MP's nearby office earlier on Monday.

Protesters chanted "trust our teachers" and "you're having a laugh, Gav" on their half-mile trip.

The government has since said teacher estimates will be used for results.

There has been growing anger after about 40% of A-level results were downgraded after the exams regulator Ofqual used an algorithm based on schools' previous results.

Protesters carrying signs made their way to Gavin Williamson's office

One of the organisers, Jess, 18, who was predicted BCC but got BDD, said the protest was important "because every student in this country should get equal fair grades. We shouldn't be reduced to an algorithm or a postcode".

Another student, Monica, also 18, said she was protesting as her results had been "severely downgraded". Her predicted grades of CCC were downgraded to CDE.

"To be downgraded by two grades is quite significant considering I didn't actually get a chance to take my A-levels, sit the exams for myself. So I can only blame the government for my downgrade," she said.

Head teacher Alun Harding said the students wanted to protest about the "significant level of disappointment and frustration they feel".

He said: "The system has been so poorly thought-through - the impact on [the students'] lives going forward is going to be enormous and they want to vent their frustration."

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Some of the students held signs with the word "U-turn" and one had a sign with Gavin Williamson pictured as a clown with a multicoloured wig and a red nose.

Members of the public cheered on demonstrators with one saying "go on kids, show them", while cars also beeped their horns in support and others stood outside their homes to clap.

Analysis: By Kathryn Stanczyszyn, BBC political reporter

A-level students in Codsall are celebrating the education secretary's U-turn after a lively protest just hours earlier.

Of course it wasn't the deciding factor - but students with placards pounding the streets and gathering outside Gavin Williamson's constituency office clearly wasn't a good look for him.

Some had lost out on university places, others were there in solidarity - downgraded but still going to college - and yet furious at the impact on their classmates.

The chant ringing out today - "trust our teachers". It seems it has been heard.

Later on Monday, it was announced that A-level and GCSE students in England would be given grades estimated by their teachers, rather than by an algorithm, after a government U-turn.

In a statement, Mr Williamson apologised for the "distress" caused.

He said: "We worked with Ofqual to construct the fairest possible model, but it is clear that the process of allocating grades has resulted in more significant inconsistencies than can be resolved through an appeals process.

'We now believe it is better to offer young people and parents certainty by moving to teacher-assessed grades for both A and AS level and GCSE results."