The location is Mayfair, London. More precisely Dartmouth House, home of the English Speaking Union (ESU) since 1927, and a fine London town house previously owned by various aristocratic families over several centuries. Winston Churchill is amongst those to have visited the building regularly, but on a cold crisp day in December 2011 it was a small group of CIO editors, contributors and senior IT industry and CIO advisers who got together to consider the list of candidates for the CIO 100 and identify the top contenders for the 2012 list.

In the refined location of Dartmouth House's Small Drawing Room, amongst walnut dining furniture, draped windows and elegant stucco decoration, the group got down to its business, directed by CIO's Editor-in-Chief, Mark Chillingworth. Sustained by copious mineral water, regular coffee injections and a fine selection of sandwiches and bon bouchée, the group spent several hours identifying those UK CIOs who have shown us all the way to perform at the highest level in 2011.

Winston's phlegmatic ghost watched over them as they debated the issues. But what was this august selection committee actually looking for? What are the attributes of a great CIO? And if you didn't make the grade this year, how can you make sure you are on the list next time around?

First of all, and somewhat paradoxically, the panel unanimously concluded that you don't actually have to be called a CIO to be a top UK CIO. The CIO's core skills are a trinity encapsulated on our own masthead: Business, technology and leadership. But our panel was well aware that the title of Chief Information Officer is not a universally held or recognised one in the UK. There are exemplar CIO's with business cards that say Chief Technology Officer, IT Director or may even carry a non-technology job title. Equally there are titular CIO's that are little more than 'laptop fixers' (to quote one panel member's description), and who definitely wouldn't make the grade. The key, therefore, is to be operating strongly across all three of these key CIO functions.

The kind of company you work in is also a significant consideration, and proved to be an area of substantial debate: Some companies are highly innovative in their use of technology to promote and push their business, whilst others are not. But to what extent does this company ethos reflect on the CIO? The general view was that a truly innovative professional would either be pushing a change agenda very hard within a more staid company, or moving on to find a place where they could exercise their skills properly. Being stuck in a backwater would quickly become a limiter for any top-flight CIO...

By extension this means that successful CIOs must be working in companies alongside other board members who also recognise the transformative power of technology and are prepared to discuss this regularly at board meetings. Having a voice on the company board is therefore essential, whether directly or via a short, sympathetic, reporting line.

Key questions asked of all the candidates on our list were; How engaged is the CIO in the company's business and strategy; how well does he or she understand the external customer; How much does the CIO contributing to business ideas (as opposed to pure technology ideas) benefiting the company?

Less surprisingly, the panel was also looking for concrete examples of innovation from CIOs under consideration.

Innovation comes in many forms: It could be the use of a new technology to achieve a business objective. It could just as easily be a new way of marshalling resources or using services or outsourcing to business advantage. The key measure was the amount of influence a CIO had on their company's strategy. Sometimes this ties in to broader company fortunes too; A CIO may be able to (need to) transform operations one year, but look a lot less innovative the following year. The broad view of the panel was that more operational roles were less likely to be able to show such transformation, and so might signify an operational CTO or IT Director (where those job titles apply) type role.

Company complexity is also a consideration. Driving through cultural and transformational change in a huge multinational corporation is clearly a much greater challenge that doing the same thing in a company of just a few hundred employees.

Equally, if the change is being driven from elsewhere (an overseas headquarters operation for example), the domestic CIO's role may be much more an operations and implementation one, and so not meet some of our other criteria, however impressive the change agenda might look.

Finally, how well does the CIO manage his or her communications, both internally and to the wider world? In many cases not that well it would seem: The panel noted the relative lack of CIOs using broader communications media like Twitter to communicate to the wider audience about what they are doing for example.

Ultimately, the single characteristic which represents the sum of the parts was the transformational one. The best CIOs are those implementing transformational change to benefit the businesses they represent. The fact that we were able to discuss a large number of candidates doing exactly that shows that, for the best candidates, current business difficulties have just inspired new and innovative solutions.

Churchill's ghost must have smiled on the CIO 100 panel as they deliberated these thorny issues. He would certainly have the necessary skills. There is no question on the leadership. His recognition of the use of technology as a transformative tool was also clear; From Dreadnoughts in 1914 to Bletchley Park in the Second World War, Churchill knew that the appropriate application of technology could transform Britain's standing. And if his 'business' during the Second World War was the continued survival of the nation, then it must surely be agreed that he was a resounding success.

See the full CIO 100 here