The Bank of England is being advised to go ahead with the splitting of retail banks from their investment arms by the government's former chief scientist, Lord Robert May – who has based his analysis on classic studies of how infection spreads through ecosystems.

"There's an idea that some banks hold that there's an invisible hand which protects them, through market action, and not too much regulation, from bad outcomes," said May. "They're on very shaky theoretical ground there."

Instead he says that the banking system functions like a network whose complexity and inter-reliance can be compared to the structure of the internet, or infection spread in livestock, or how HIV spreads among humans.

May, an expert in infectious diseases who is a professor at Oxford University and Imperial College, is one of a team of scientists brought together by the Bank chairman Mervyn King since 2006 to try to apply theoretical studies to the question of how best to protect the banking system.

He has written a scientific paper on the topic with Andrew Haldane, the executive director of financial stability at the Bankof England, which is now being considered for publication by the science journal Nature.

May said that the failures of large banks can put the entire system at risk just as the failure of key internet sites, or HIV-infected people who have sex with multiple partners, can damage their respective networks.

"There's a paradox that actions that might make sense for each bank individually might not make sense when they're all together at all," May told the Guardian. A key example of those actions, he said, is where a bank has both a retail and investment arm.

"The studies from other fields show that if you want to maximise the vulnerability of the system, then you mix those two together. It's like the spread of infectious disease," May said. "And if you look at the models, it's not surprising that you find that the system would be more stable if the banks held bigger reserves in boom times, and smaller ones in lean times."

King is the first non-banker to head the Bank of England – and Lord May praised his "more academic" approach to the issue of ensuring stability by calling in scientists: "He's very concerned about the dynamics of the system. Above all, we don't want regulations based on feelings; we want an understanding of what does what before we change the rules."

Haldane clearly thinks along similar lines: he has previously compared the effects of the failure of the investment bank Lehman Brothers in September 2008 to the effects of SARS, the flu-like respiratory illness that almost turned into a pandemic in 2002.

May said that he has been working on a committee with the Bank of England since 2008 to try to apply existing scientific knowledge about topics such as ecosystems to the banking system.

May said that he had commented to Haldane that if the financial system were like natural ecosystems, it should be robust: "I said to him 'in nature, it's survival of the fittest'. He said to me: 'No – with banks, it's survival of the fattest.'"