Her achievement is more poignant because she has successfully turned around a London school while fighting cancer.
When Mrs Metcalf joined Chiswick Community School in Hounslow 10 years ago it was what would now be described as failing.
Now its results are in the top 5 per cent for schools with a comparable intake - more remarkable in that about two dozen languages are spoken by the 1,200 pupils at the highly ethnically diverse school. More than half of 16-year-olds now gain at least five good GCSEs, up from a third.
Mrs Metcalf reflected on what the school had achieved: "You break out of a vicious circle into a virtuous circle of success. It was a difficult process. It has required a lot of faith."
Mrs Metcalf feels her commitment to teaching helped her fight off breast cancer and was testament to how people should not give in to illness. She said: "When I was first ill there was the issue 'do I press on or do I quit and do something else?' I just thought I could become a professional invalid or get on with my life."
Her illness started seven years ago and she has recently had a relapse and is currently undergoing treatment. She said: "It is not a death sentence. You don't have to abandon your life. I really love my job. It is a big part of my life."
Mrs Metcalf hopes her success will encourage others to fight on when facing such adversity.
A knighthood has been awarded to Bob Salisbury for rescuing the Garibaldi School in Mansfield, Nottinghamshire.
Falling rolls threatened it with closure eight years ago when he joined and only four schools in the country had a worse academic record.
Now pupils regularly win Oxbridge places, despite the school's position in one of the country's most deprived areas.
Mr Salisbury has not been frightened to court controversy in turning the school around. Most recently, mothers were asked to sit in on classes when their children were being unruly.
He said of his methods: "I think you have to project fearlessness. You have to do things that will support your school and community. Sometimes you have to ruffle feathers. Nothing changes unless there is a challenge to things."
FE Honours, page 32