The health secretary has written to clinical commissioning groups to assure them that that they will be in control over crucial issues such as competition, integration, and buying support services.

Andrew Lansley sent out a letter on 16 February to all CCG leads, stressing that CCGs will be free from top-down interference, free to work with whoever they choose, and free to commission the services that they believe are best for patients.

The letter said: “I know many of you may have read that you will be forced to fragment services, or to put services out to tender. This is absolutely not the case.

“It is a fundamental principle of the [Health Bill] that you as commissioners, not the secretary of state and not regulators should decide when and how competitions should be used… Monitor would not have the power to force you to put services out to competition.”

Mr Lansley also said CCGs would be able to buy commissioning support from “whatever organisations in whichever sectors are best able to meet your needs”. “Every effort” was being made to enable CCGs to have choice over commissioning support provider before April 2013 where possible.

CCGs would not be forced to use private sector commissioning support.

The NHS Commissioning Board would be responsible for ensuring CCGs’ autonomy, while clinical senates would not be allowed to “second-guess” decisions taken by commissioners.

Mr Lansley also said: “You will no doubt be aware of some of the interest the Bill’s return to the House of Lords is attracting in the media.

“This is not unusual for high-profile legislation, and I would like to reassure you that the government remains fully committed to the successful passage of the Health and Social Care Bill.”

Charles Alessi, chair of the National Association of Primary Care and a senior member of the Clinical Commissioning Coalition, said the letter was “timely and most welcome”.

He said: “It provides a much needed measure of reassurance. Many CCGs have laboured under the impression that they will not be able to choose the source of their commissioning support, which the secretary of state has now unequivocally clarified.”

The letter had also provided a strong defence for CCGs under pressure to continue with existing commissioning arrangements that they feel are no longer fit for purpose, Dr Alessi said.

On competition, “this letter makes the position very clear. CCGs, and CCGs alone will decide when and how competition, if at all, should be used in the interest of patients,” he added.