"I thought outsourcing was more expensive and the study proved that it was far more expensive," Brewer explains.
"It also showed that shared services wouldn't deliver much more than we could internally in terms of efficiency gains. If you compare the benefit of sharing services with the cost of setting up a shared-services arrangement - not to mention the governance issues and the disruption - then it wasn't worth doing. It would also require a large upfront investment to reconfigure our infrastructures and methodologies, which in the short term isn't worth it."
The benchmarking, which Brewer calls "very forensic" and based on "solidly grounded facts, not facile suppositions", did confirm that both Kingston and St George's were running "lean and mean", and 15% more efficiently than similarly benchmarked peers.
Brewer and Campbell may have decided not to share services for now, but that doesn't mean they, and other IT directors across London's hospital trusts, don't share ideas, experiences and learnings on a regular basis.
"Our default strategy is convergence and collaboration - if we're both procuring a rostering system, let's get the same one unless there are good reasons to do otherwise. We might make it one project with one project manager," says Brewer.
"We've got a long-standing IT directors' forum that meets every couple of months," he adds. "We all do things at different times, but the London Procurement Partnership will ask people what their plans are and get hospitals together to support procurement, while the London Programme for IT is part of the strategic health authority - they've been much more collaborative with us rather than trying to telling us what to do."
Talk of the London Programme for IT brings us inevitably to the NHS's National Programme for IT (NPfIT). The £12 billion programme to streamline technology uptake in the NHS - written off by the Coalition government in 2011 nine years after it was launched by its Labour predecessor - is rarely mentioned without the adjective 'much-maligned', but Brewer, for one, will be sad to see it go.
"The NPfIT for us has been very positive. Because of where we were it made sense for us to adopt the acute hospital systems that were being offered," he explains.
"It gave us funding and provided contracts that we didn't have to go out and procure, and I don't believe there's a great deal of difference between the electronic patient record (EPR) systems anyway.
"We went live in 2009 with [EPR system] Cerner Millennium, and we were arguably the most successful hospital to go live with the system. There was a lot of noise in the press about systems going live and failing, but you didn't hear anything about us because we did it successfully.
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