The Cabinet Office’s Flex programme has significant potential.

Although only the Department for Innovation, Universities and Skills (Dius) and the Office of National Statistics have signed up so far, as many as 20 public sector organisations are considering it.

The 2,000-employee agency tipped to be joining imminently will take it near, if not over, the 10,000 threshold where the price for everyone drops by 20 per cent.

And if take-up passes the 100,000 specified in the framework ­ which is not out of the question, particularly if the deal proves attractive to local councils ­ the cost implications are truly significant.

Much is riding on Flex. Public sector budgets are tight, and shared services are crucial for plans to cut public sector IT spend by a fifth and desktop costs by 40 per cent.

The programme’s structure is breaking new ground. As costs come down, for example, existing users will get a rebate, and a customer board will decide whether the windfall goes back to departments or is re-invested.

But Flex’s success is not simply a matter of innovative contracts; or even of addressing the cultural silos that bedevil joined-up government schemes. Above everything else, the technology itself will have to work.

After months of careful design work, the specification of the standard platform is agreed and will go into testing in February, for rollout to the Cabinet Office’s 2,500 employees between March and June.

But the timetable is awfully tight. The Dius deal signed this week expects rollout to start next summer, and it is likely many “warm” organisations will wait to see what happens with the early adopters before they commit.

There are many lessons to be learned from problematic government IT. But for Flex the most important will be about the relationship between the customer and the supplier.

It will need to be a triumph of clear communication. Get that right, and that significant potential may start to be realised.