Failing schools in Wales will be eradicated by September next year if teachers have the "will" to make it happen, according to Estyn chief inspector Ann Keane.
Schools have the potential to achieve a quick turnaround in standards and results if there is strong leadership and commitment from teachers.
Ms Keane said the goal of having no "failing" schools by September 2012 - outlined in a radical blueprint for improvement commissioned by the Welsh Government - is achievable if heads and teachers pull together.
This is despite new figures that show almost half the schools inspected in the last year needed some form of follow-up visit from the inspectorate.
Speaking to TES Cymru, Ms Keane said: "It (the target) is feasible if there's a national commitment to improving standards in literacy and numeracy. If schools put skills at the heart of their curriculum planning and start delivering on that quality they can achieve a quick turnaround.
"There's excellent practice out there and I think schools can learn from each other really quickly. I want to see coasting schools up their game.
"To turn a school around and get it to be one of the best needs strong leadership and a professional, moral and emotional commitment from members of staff. Schools have the tools, if the will is there. It's always a hearts-and-minds job."
Earlier this year a major report on the structure of education services in Wales said that as a minimum standard, no school should be rated unsatisfactory following an Estyn inspection after September 2012, and by 2015 all schools should be rated better than adequate.
Education minister Leighton Andrews has accepted all of the report's recommendations.
However, Ms Keane revealed that 45 per cent of the 244 schools inspected in the last academic year - the first of Estyn's new common inspection framework - needed some form of follow-up visit.
The figure compares to just 30 per cent over the course of the last inspection cycle.
Of that 45 per cent, 5 per cent of schools were in the most serious categories - special measures or requiring significant improvement - up from 4 per cent in the last cycle.
Although Mr Andrews recently called the figures "staggering", Ms Keane said they represented a more realistic assessment of the state of Wales's schools than previously.
"It is more realistic because we have got a much tighter focus on standards now," she said. "The quality of data is much better and we are focusing on skills instead of content."
Teaching unions are sceptical about the possibility of schools making such rapid improvement without more support.
Dr Philip Dixon, director of ATL Cymru, said: "These figures suggest there will be no quick fixes.
"I would be surprised if we could go from 45 per cent to zero in the space of a year. It would be quite remarkable in the history of education.
"The will is there from teachers, but they will need a lot of extra support. I think the target is overly ambitious."
Gareth Jones, secretary of heads' union ASCL Cymru, said: "We want all schools to be superb and we know what needs to be done, but the reality is that the ability to do it can be confounded by circumstances.
"You can achieve quick wins, but they are not always the best in the long run. Strong challenge to schools and leaders must be balanced by strong support."
Original headline: We can be rid of failing schools in 12 months, claims Estyn chief