Constant changes in the requirements for Choose and Book by the Department of Health and lack of clarity on the boundaries of patient choice have created delays in implementation and are increasing the risk of a "sub-optimal" electronic booking system being delivered.

This was the tough message delivered to NHS senior managers at the NHS Confederation last week by NHS IT director general Richard Granger, indicating that the perpetual revolution in health policy is causing problems for those designing the systems needed to deliver reforms.

Granger said that his brief on Choose and Book has been repeatedly rewritten and extended: "What I was contracted to put in place is an e-referral system. The requirement is now much more complex – that you keep your local systems and 180-plus hospital legacy systems."

He told a packed audience that many of them had directly contributed to delays by failing to complete and return a Directory of Services (DOS) on time, detailing what hospital services can be electronically booked.

To try and deal with delays in the delivery of upgrades to GP systems to enable them to connect with Choose and Book over the NHS spine, Connecting for Health has already had to develop additional stand-alone systems known ‘Indirectly Bookable Services’. Even with these additional systems the goal of having Choose and Book 80% implemented by the end of December looks unlikely.

Granger didn’t respond to audience questions about delivery schedules but said he and his team faced "a constantly changing requirement" with the system now also required to take in areas like dentistry. "I’m concerned this just keeps growing," said Granger. "It just keeps snowballing."

E-Health Insider understands that the changes in requirement on Choose and Book are being driven by the DH’s patient access team led by Margaret Edwards.

At the NHS Confederation conference Granger added that one of the issues that had to be determined nationally was "where the boundaries of patient choice and self-determination are – we can’t just keep expanding them."

The NHS IT director general said that constant changes in the scope of the project increased its risks of failure. "I’d actually like to know what the endgame is, otherwise we risk sub-optimising the system."