The main job of Vault OS is to perform the core function of a bank: essentially, maintaining a huge ledger. Each instance of the OS will run its own private blockchain and cryptographic ledger, hosted as a service by ThoughtMachine. The ledger is tamper-proof and transparent, it means that transactions can be processed without the need for third-party verification. “Most of the banks are using systems that were written in the 80s and 90s, and they just are not ready for the security-conscious internet app age at all,” Taylor told Reuters. “What the blockchain does is provide a very secure way of storing transactions.” Taylor said, major high-street banks were spending around a billion pounds ($1.3 billion) a year on computer technology, much of which he said was being used for propping up the current “legacy” systems rather than on any innovative technology. The system negates the need for costly in-house data centres, as it uses cloud-based systems, which banks can use on a “pay-as-you-go” basis, which means that there is no single point of failure. The start-up has been working with about ten banks, Taylor said, at least one of which would be starting a trial using the new system in August. He expects the system to be up-and-running within about a year.