Julia Simon, until earlier this month the head of NHS England's commissioning policy unit and its co-commissioning of primary care programme director, said forcing health and care organisations to come together so quickly to draw up the complex plans was likely to backfire.
Up against tight deadlines, organisations were likely to make unrealistic financial forecasts and claims about benefits to patient care, she warned.
Speaking to GPonline at a London healthcare conference, Ms Simon said the timescale imposed on health and care organisations to draw up STPs was 'unrealistic' and 'an unfair ask'.
‘Everyone will submit a plan, because they have to,' Ms Simon said. 'But it means there is a lot of blue sky thinking and then you have a lot of lies in the system about the financial position, benefits that will be delivered - it’s just a construct, not a reality.'
Hastily drawn-up plans would lead to financial problems, she said. ‘Ultimately it means bankruptcy in some areas.’
Ms Simon warned that STP areas had not been given enough time to develop and embed trust between the 'players involved'.
Some areas, she said, could build on relationships that already existed between different organisations across primary and acute services, and health and social care. But in others there was a legacy of bad relationships and disagreement that could undermine effective planning.
Speaking during a debate at the Commissioning in Healthcare conference in London on Wednesday, she also questioned the lack of patient and public involvement in STPs - dubbed 'secret NHS plans' by critics.
'I haven’t seen any genuine patient and public engagement yet,' said the former NHS England official. 'I think it is entirely driven by the speed that NHS England has imposed on this process which is, frankly, kind of mad.
'It’s mad. I think we will see a lot of catching up on that end, but to do that right, to do a statutory consultation - it's three months. They don’t have three months.' Referring to the speed at which STPs were being asked to draw up plans, she said it was 'actually shameful, the way we have done it'.
Other speakers at the event also questioned the pace at which STPs were being brought together.
Nuffield Trust policy fellow Holly Holder said many people within CCGs that her research team had spoken to 'seem to think there is a role for something at STP level'.
But she said that where in the past relationships had been built up over time between health and care organisations to drive integration, 'now areas are working together where those relationships do not exist, and they have to form those relationships very quickly, and that is difficult to do'.
NHS Clinical Commissioners co-chair Graham Jackson also said the timeframe and secrecy around STPs had been ridiculous.