The government's NHS reforms may fail to liberate the NHS as central organisations bid to maintain control over local decision making, the King's Fund has warned.
The think tank carried out a simulation exercise with NHS Lincolnshire to look at how the NHS will function in 2013/14. The 24-hour exercise simulated a year of NHS activity.
Commissioning for the future showed that central NHS organisations actively tried to manage local decisions as local groups looked to them for guidance.
The researchers said GPs were often 'overwhelmed' by the number of activities they were expected to take part in.
Patient involvement in decision making was limited, the exercise found.
The King's Fund said the NHS Commissioning Board was one of the 'most active players' in the exercise.
It tried to influence consortia development, arbitrate in disputes with providers and spent a lot of time guiding consortia on their commissioning function, the researchers said.
King's Fund director of policy Anna Dixon warned that because of the financial challenge central bodies in the new NHS will want to place 'a tight grip on those that hold the purse strings at a local level'.
She said: 'The risk is that, far from liberating the NHS, these reforms will stifle the enthusiasm and innovation among GP consortia that we witnessed in the simulation.'
Meanwhile, the exercise showed that GPs felt 'pressurised and overwhelmed' by the number of responsibilities they were expected to take on.
GPs found it difficult to grasp the rules of the new system and struggled to take charge of the agenda, the simulation found.
The researchers said: 'At the end of the simulation... the GP consortia had no signed contracts and no financial plans that were felt to be credible by the NHS Commissioning Board.'