Southend's grammar schools have been easily outperformed by other local schools in a different type of league table.

It is measured on how pupils improved throughout their school career.

Only one of the four grammar schools, Westcliff High School for Boys, made it into the top three schools in Southend and Rochford.

At Southend High School for Boys, pupils on average failed to do as well as expected.

The table was topped by comprehensive King Edmund School and the Catholic St Bernard's High School.

King Edmund's Deputy Head Martin Haynes said: "We are not surprised at all. We have had very high value added for the past four years.

It is down to the staff, who work very hard with the students. We tailor the range of courses to suit the ability of the students.

"We do fast-track students as well. There are students in this school who are taking GCSEs at the end of Year 9, and we do have students taking GCSEs at the end of Year 10, and AS levels at the end of Year 11."

Sally Carr, Southend Council's education portfolio holder, said value added was the "key measure" for schools.

She said: "It is a school's duty to ensure children continue to improve. I am sure this is a dip for Southend Boys' School compared to normal. I know adding value is paramount in the minds of heads and staff.

"It is value added which makes the difference to the children and no school really should fail on it." The figures are calculated by comparing pupils' performance at the end of Year 6, when they leave primary school, and at the end of Year 11, when they take GCSEs.

If the score is 1,000, this means pupils have, on average, performed as their Year 6 results would suggest.

A higher figure means they have overachieved, a lower one means they have underachieved.