The increase may be down to the fact that younger teachers are more likely to have degrees. Also, fewer trainees are doing general bachelors degrees in education, and many with the Certificate of Education - now phased out - have retired.
Combining the figures for degrees with other post-school courses shows the proportion of teachers with relevant qualifications beyond A-level has risen from 57 to 62 per cent. The study, by the National Foundation for Educational Research, said the expertise meant secondary schools were well placed to teach many of the new 14 to 19 diplomas.
The improvements did not stop the Daily Express calling the study "damning", because it showed half of secondary teachers had no degree in their subjects. However, the report did show the proportion of lessons taught by teachers with relevant post A-level qualifications had dipped slightly since 2002, from 83 to 79 per cent. This is likely to be linked to the rise of newer subjects such as citizenship, normally taught by specialists in other areas. Only one in 20 teaching it have a relevant post A-level qualification. There has also been an increase in popularity of ICT and religious studies - both subjects where less than half of teachers have a relevant degree.
Professor John Howson, a recruitment analyst, said: "There have been improvements in the overall level of qualifications, but this is to be expected after an impressive six years of recruitment, with schools given more choice in whom they employ."
He said he was more alarmed by the gap in qualifications between schools in the most and least deprived areas. One of the starkest examples was in geography. In schools with the most pupils eligible for free meals, 65 per cent of teachers had relevant qualifications, while 85 per cent had them in schools with the most socially advantaged intakes. In maths, only 56 per cent of teachers in comprehensives in areas with grammar schools had a relevant qualification, compared to 88 per cent in the grammars.
Professor Howson said this figure was "frightening" and exposed some of the most vulnerable children to the least qualified teachers. He is also concerned about science. Here, an impressive 90 per cent of teachers have post A-level qualifications, but there are still desperate shortages of chemistry and physics specialists. He said: "Overall figures of a generally better qualified workforce mask areas where the Government has become complacent."
The Royal Society said they were concerned that physics lessons taught by specialists has dropped from 94 to 91 per cent in five years.
Mary Bousted, general secretary of the Association of Teachers and Lecturers, agreed that differences between rich and poor schools gave cause for concern. But she stressed that subject knowledge was not the only important aspect of teaching. "Teachers need the skills to offer the best learning experiences for all their pupils," she said.
Jim Knight, schools minister, said the lack of science and maths graduates was "not unique to teaching".
The Secondary School Curriculum Staffing Survey 2007 is at www.dfes.gov.uk.