Risk logs from the then NHS Commissioning Board show it expected problems that could put patient safety at risk.
In February, just weeks before the national roll-out deadline, the logs highlight 'numerous recent performance issues in live areas' that raised the risk of affecting patient safety.
The risk that 'operational problems may result in patient safety issues' was assessed as 'very likely', with 'significant' impact.
When NHS 111 launched over March and early April, widespread problems prompted GP leaders to call for it to be halted.
The risk logs, dated 22 February, reveal fears of a 'loss of national grip of quality and clinical governance of the service post roll-out'. This was also rated 'very likely', with 'significant' impact.
There were also fears at the NHS Commissioning Board - now NHS England - that 'lack of priority and resources' for the roll-out during the NHS transition period could cause delays and 'lack of clinical engagement'.
Other risks scored in February as 'likely', with 'significant' impact, included:
- 'Loss of national 111 ownership and performance management during transition.'
- 'Scope creep or loss of focus as a result of new direction for 111 compromises the delivery of the current 111 service.'
A spokeswoman for NHS England said the 'final decision to roll out was taken on a site-by-site basis by local commissioners and providers, after operational, clinical and technical readiness testing'.
She added: 'The risk register from 22 February 2013 represents a snapshot in time within the NHS 111 programme. It was used by senior colleagues to assess risks ... and also presents mitigating actions.'
GP leaders warned before and during roll-out of the service that patient safety was at risk if commissioners tried to launch the service to deadline for political expediency.
GP revealed exclusively in July that one of the largest 111 providers, NHS Direct, identified concerns about understaffing and call volumes weeks before problems arose.
A damning report published in July by NHS England into failings found local commissioners lacked necessary skills and tried to cut costs, providers lacked capacity and capability, and NHS England failed to provide proper central oversight and support.
NHS England deputy chief executive Dame Barbara Hakin has said £15m for winter pressures will pay for an extra 200 call handlers and 60 clinicians for NHS 111.
The BMA said when the funding was announced in August that it was 'papering over the cracks' and would be better spent on general practice.