GPs' surgeries must offer patients "real choice" over whether they want to be treated by the NHS or the private sector, a think-tank has said.
The right-wing organisation Civitas issued the warning as it claimed 713,513 (18%) of patients needing elective treatment are waiting longer than 36 weeks from referral, while 387,152 (10%) are waiting more than a year.
This goes against government figures which show 60% of patients were admitted for treatment within the 18-week target during October, an increase on the 57% recorded the previous month.
Civitas also warned of significant differences in waiting times, as 33% of patients at Hastings and Rother Primary Care Trust are treated within 18 weeks, compared with 82% in Blackpool PCT and Telford and Wrekin PCT.
James Gubb, director of the health unit at Civitas, said: "Instead of political targets, performance should be driven by choice and competition - a self-sustaining and much more positive mechanism for change.
"If this means more patients choosing to have their treatment in the independent sector or the better NHS hospitals, then these should be allowed to expand in response.
"GPs must be in the driving seat, offering patients real choice and ensuring this mechanism is available."
But health minister Ben Bradshaw dismissed the Civitas claims as "scaremongering", and said the NHS has made great strides over the past 10 years.