Schools around Haverhill failed to match their impressive GCSE performance in the A-Levels.
Samuel Ward Academy ranked 28th out of 37 Suffolk Sixth Form Colleges, with Castle Manor Academy coming in 32nd.
Sandwiched between them was West Suffolk College in Bury St Edmunds in 31st.
The best Sixth Form College is Suffolk was St Benedict’s Catholic School.
It also came best nationally for A Levels, with only two other schools and private and selective schools above it in the UK.
School head Hugh O’Neill said: “We knew our A Level results in 2012 were our best ever. We hoped that this would show up in the league tables, and it has.
“It’s especially important for us this year, because everyone knows that our GCSE results were hugely disappointing.
“We think that the A Level results confirm that we are an outstanding school, and the GCSE results simply aren’t a fair reflection of what our students achieve.”
On average in Suffolk the number of points per student for AS and A Levels increased by 27 compared to the previous year, meaning an average pupils scored one grade higher than in 2011.
This drove the typical student up from three Bs to two Bs and an A.
Hedingham Sixth Form College came 35th out of Essex’s 57 colleges.
In Cambridgeshire, Hills Road came fifth out of the county’s 31 sixth forms while Long Road came in 21st.
Numerous Haverhill students continue their post GCSE studies at the two Cambridge colleges.
Councillor Graham Newman, Suffolk County Council’s cabinet member for education and young people, said: “Our A Level results show how the grade boundary alteration has warped how our schools appear in the league tables.
“The same schools that have slipped down the GCSE league tables have done fantastically with their A Level results, where grade boundaries have not been changed at the last minute and quite often the same teachers have been teaching both GCSE and A Level pupils.”
For all the latest news see Thursday’s (February 7) Echo.