RCGP chair Dr Helen Stokes-Lampard warned that the imbalance meant general practice was losing a growing number of GPs from permanent roles at the worst possible time.
'People who have resigned their partnership because they are burned out and disillusioned with the pressure they are under are the victims of this terrible negative cycle we have got into,' she said.
'The battle we have been fighting to get more resource for the profession is to address this problem. But inevitably change is slow - we are losing people from partnerships, losing people from salaried positions into locum work at exactly the time when that is the last thing we need.'
Estimates have put the number of GPs working as locums at more than 17,000 - equivalent to up to a third of the total workforce - although accurate data is unavailable because official data largely exclude locums.
But more and more GPs are switching to locum work. GPonline reported earlier this year that locums carry out more than a fifth of total workload at one in seven GP practices, and this month revealed that one in six GPs who describe themselves as locums now were partners a year ago.
In an exclusive interview with GPonline, Dr Stokes-Lampard said she did not want to see the proportion of GPs working in locum roles rise any higher than the current level.
'I would rather it didn’t go any higher,' she said. 'We know there are people who are doing locum work who would rather not be doing locum work, who would rather be in salaried or partnership jobs but the environment is so toxic they feel they have no other choice.
'Those are the people who we need to be targeting, those are the people whose lives we need to be making better and getting them back into the stability they want.
'But they’re doing that because they’re desperate. They can earn more working as locums. And while we will always need locums - there will always be locums in the system, and we are always very grateful for locums and we need them to help us at times of crisis - actually what most GPs value is building up a relationship with patients over a period of time where you see the full cycle of illness, wellness, health and wellbeing. You can only do that when you are in the same place for a length of time.'
Dr Stokes-Lampard stressed she did not mean that locum jobs were bad and other GP jobs good. 'We need our locums, desperately need them. But we need to make salaried and partnership roles more attractive again. That is the reality of the situation. This is not about locums bad, other jobs good - this is about why are people making these decisions, it’s a big strong message to policymakers.'
A career portfolio GP herself, who has combined a part-time partnership role with medical education and research work, she said that general practice is the 'most flexible career in medicine'.
But she admits that 'NHS general practice would fall over' if all GPs opted to work only a few days on the frontline each week.
'A system where everybody only does the bits that they want only works if there is a lot of slack in it. For those that want flexibility, fantastic, they are in the best job in the world for flexibility actually, but the people who are locums and don’t want to be - those are the ones we need to provide a better deal for, and for those who are contemplating resigning salaried jobs or parnerships to become locums we want to do everything we can to stop that, to stop that continued trend.
'You can’t force people, it’s about incentives. Making it more attractive. When I qualified as a GP this wasn’t an issue - everyone wanted to be a partner or a salaried doctor and you locumed for convenience at certain stages of your life. Now suddenly locuming is the attractive thing to do, and that balance is wrong.'