The BMA says this is because current consultations with patients are longer and more complex and GPs are increasingly treating patients previously cared for in hospitals, raising the intensity and quality of workload to an all-time high.
Dr Laurence Buckman, chairman of the BMA's GPs committee, commenting on the workload survey findings that full-time GP partners work an average 44.4 hour week, said: "Since the last workload survey in 1992/3, the average length of a consultation has risen from 8.4 minutes to 11.7 minutes.
Research clearly shows that longer consultations deliver better care for patients. On top of this, practices are achieving outstandingly high scores on the Quality and Outcomes Framework in the new GP contract. The survey shows that hard working teams are providing higher quality care for their patients."
Fair comparisons with the last GP workload survey in 1992/3 are difficult because so much has changed in the intervening years, says the report. Different methodologies and analyses were used in the two surveys. For example, figures for consultation numbers and hours worked in the earlier report include out-of-hours consultations which are not covered in the 2006/7 survey results, nor was the content or complexity of consultations analysed.
Dr Buckman said: "Since the early 1990s there have been significant contractual changes for GPs, and an increase in the number of salaried doctors and the number of GPs working less than full time. However today's results do show that the average weekly hours for GPs are very similar to those in 1992/3 if you exclude out-of-hours work which was not measured in the new survey.
"What has changed is the way we work. Intensity has rocketed. Patient care that used to routinely take place in a hospital setting - such as diabetic care, cardiac care and asthma care, is now routinely done in general practice. It used to be commonplace to be called to a child with uncontrolled asthma, or a patient with heart failure and send them to hospital. Now it's a rare occurrence.
"The quality and complexity of GP care has altered out of all recognition from the consultations of 14 years ago and GPs are much more closely scrutinised to ensure that this quality is maintained. As a result, patients are looked after better and nearer their own homes.
The way that GPs work now, with their teams, is better for patients, better for the NHS, but it means that GPs are working under much greater pressure, dealing with increasingly complex cases and the other members of the practice team see the more straightforward problems."
The workload survey shows that on average GP practices have 24 members of staff, with GP partners - the doctors who also run the business side of providing general practice for the NHS - working longer hours than other staff.
Dr Buckman said: "Full time GP partners see over 100 patients a week face to face, give advice to another 20 on the phone, and on top of this make home visits, see elderly patients in care homes and run clinics. The survey shows that although all clinicians in the practice team work hard seeing patients, GPs provide most of the consultation workload."