Colchester Royal Grammar School has finished top of the national A-level results league table.
Students at the school in Lexden Road outperformed the rest of the country by some distance, averaging 1477.1 points per candidate and 223.9 per exam.
The second-placed school, Altrincham Grammar School for Girls, Greater Manchester, averaged 1283.6 points per pupil and 252.8 per exam.
The points are issued with Grade A* scores getting 300 points, an A scoring 270 points, a B scoring 240 points, a C picking up 210, a D scoring 180 and an E grade is worth 150 points.
However, nationally the figures show that thousands of teenagers are being let down by their secondary schools, with the poorest and brightest being failed the most.
An analysis of the new league tables, which cover every secondary in England, suggest that many schools are failing to help bright pupils achieve their potential.
The tables, based on GCSE, as well as A-level results, for 2011, show that overall, 107 secondary schools were below the Government's target in 2011.
Schools minister Nick Gibb said that the tables showed a "shocking waste of talent".
Schools that fail to meet the strict thresholds have been warned they are at risk of closure or being taken over if they do not improve.
Shadow education secretary Stephen Twigg said: "These results show that the Government needs a clear plan to raise standards in all schools in England."