Many challenge schools are improving fast
Hundreds of England's secondary schools are analysing their GCSE results to see if they have nudged above a new government target.
In June, ministers warned schools which did not have 30% of pupils getting five good GCSEs including English and maths could face take-over or closure.
Manchester, which had 13 schools below the benchmark, has said that eight have now moved above the threshold.
But only one of the 10 Bristol schools below 30% last year has topped it.
This was Bristol Metropolitan College which recorded 34% of pupils making the benchmark compared to 29% the previous year, when the school was still called Whitefield Fishponds Community School.
However, all the other schools except for two, improved their results. The greatest improvement came at Hartcliff Engineering Community College, which was up to 26% from 17% on last year.
Bristol City Council leader Helen Holland said: "We owe it to our young people to do everything we can to help them fulfil their potential.
"We have already set in motion a number of measures that are bringing about improved results and we are determined to keep up the momentum of positive change. Raising school standards is at the heart of all our work with children and young people."
In Manchester, the biggest improvement was recorded at St Peter's RC High, where 47% of pupils got five good GCSEs including English and maths this year compared with 27% last year.
Director of children's services at Manchester City Council, Pauline Newman, said the improvement reflected the hard work of young people, parents, carers and schools.
"We will continue to work closely with all schools in Manchester, to support them in further improving outcomes for young people.
"With the unprecedented programme of investment now underway in school buildings and a range of exciting developments ahead in the way pupils learn, I am sure we can look forward to further stories of success in the future."
In Birmingham, where 27 schools are included in the National Challenge programme, 10 schools have edged above the 30% target.
Early estimates also show that the proportion of pupils achieving five A* to C, including English and maths, has risen from 40.7% in 2007 to 44.5% for city council schools overall.
Birmingham City Council Cabinet member for children, young people and families Councillor Les Lawrence said: "This achievement is a clear message to all those who have reported on the city in a negative manner, following the publication of the national challenge target, that we are making terrific sustained progress and we are getting it right."
Schools minister Andrew Adonis congratulated all pupils and all schools today for their results and hard work.
"As we said at the launch of National Challenge, many National Challenge schools are improving fast, with strong leadership and high aspirations.
"National Challenge schools will still be receiving extra funding, help and support to help them continue to improve and sustain those improvements for the long term."
Christine Blower, acting general secretary of the National Union of Teachers said: "We still do have a great concern about the government's arbitrary target of branding all schools as failures who do not achieve 30% A-Cs at GCSE.
"We hope that those schools which have not got the 30% do not suffer any decrease in their intake, and are offered encouragement to build on their success, not threatened with closure."