The government's plan to put its IT infrastructure in the cloud is heavily reliant on the supplier community providing working examples and pilots.
IT services firm Capgemini, which is running a pilot of a full potential G-cloud, has outlined to Computer Weekly how it might look from within.
The first part of the G-cloud strategy is to rationalise datacentres using virtualisation technology. For example, Suffolk says central government has 130 datacentres and 9,000 server rooms. Add the police to that and you have another 80-plus datacentres. Virtualisation could lead to an 80% reduction in the datacentre space required.
Then there are shared services, which allow code to be re-used in applications across public sector departments and cloud-based services that government departments and citizens can access.
But to realise this technology vision the government needs to rely on suppliers to contribute to the development. Some of the cloud projects being run by Wipro, Infosys and Capgemini showcase advanced technologies that the government could draw-on.
Capgemini and HP are among a group of suppliers running pilots for the government.
Capgemini CTO Karl Deacon says the suppliers are educating the government about the capabilities of cloud computing.
Capgemini is building two separate cloud computing projects for the government to evaluate.
One uses technology from the Cisco, EMC and VMware joint venture Acadia Solutions to provide the IT infrastructure in the cloud, as the first layer of the cloud stack. Then it has put Cordys in the cloud to provide a development platform as a service. The final layer will be applications available on demand.
The other pilot is built on a Microsoft infrastructure in the cloud. It will have what Deacon describes as an "Azure-like" development platform in the second layer with software as a service, such as Microsoft Business Productivity Online Service (BPOS), making up the other layer of the stack.
Having the infrastructure in the cloud will help the government rationalise its sprawling IT assets. The potential savings through a reduction in required datacentres alone are massive.
Providing software applications in the cloud offers further savings. Government departments will be able to re-use approved applications, eliminating the need for further procurement rounds. This could bring significant savings, says Deacon.
"To procure an ERP system for a large government department there is a big procurement process. This happens across every department," he says.
Departments can also pay for software on a pay-per-use basis, bringing further savings. But perhaps the biggest savings over time could come from putting application development in the cloud. By storing every line of code in a cloud, departments can re-use them whenever they build services.
Fragments of code might, for example, include a credit check or a citizen identification system. "You could build an entire HR system without writing a single line of code," says Deacon. "And to set up a development project can take literally 15 minutes."
Paul Watson, professor of computer science at Newcastle University, says cloud-based middleware for application development - such as Cordys and Azure in the Capgemini pilots - is critical to the success of the government's G-cloud initiative.
In the past if it could take months to set up an IT project, but with cloud computing it can take minutes. "Someone might have an idea when coming into work. They then had to write a proposal to get the money for the machines and wait months before they get it. Then they have to find the machine rooms in which to put the resources," he says.
But Watson warns, "Clouds have lots of potential to transform IT for government, but building scalable distributed systems is really difficult and clouds do not make this easier."
The real benefit will come by enabling the government to re-engineer government processes across departments, says Deacon.
"The government would have the extra money and time required to transfer to shared services. In the past it was very expensive to do," he says.