After many years of immensely careful planning the Bank of England has migrated to its new Real Time Gross Settlements (RTGS) engine.

That’s a new hardware and software stack, which on day one of operations on Monday, settled bank payments totalling £778 billion. 

The switch was revealed by Dave Ramsden, deputy governor, markets and banking, at the Innovate Finance Global Summit 2025 on Tuesday.

Whilst the bank has revealed very little indeed about the core technology stack, which has been delivered in partnership with Accenture, it has moved off a decades-old, brittle technology stack that has imposed immense restrictions on the onboarding of new banks to the RTGS.

Out with the Sybase and mainframes?

The BOE earlier described the RTGS as built on 26-year-old infrastructure.

The legacy RTGS system was also “difficult to understand and maintain” as consultants at Deloitte put it in 2014 when tasked with conducting a post-mortem into a nine-hour outage: “...incremental changes have resulted in an increase in complexity… In combination with the ageing development language used to program RTGS, the result is a system which is… heavily reliant on the skills and experience of the team to support it and more susceptible to errors which take longer to diagnose.

“There is an increased risk of functional or configuration changes causing errors and if or when the system does fail it may take longer to resolve…”

New interfaces with DLT systems?

The new system will not just let it onboard new firms to the RTGS faster and let them settle in central bank money, but potentially dramatically extend settlement hours and even “enable RTGS to interface with tokenised asset ledgers” Ramsden said this week, hinting at the scale of the Bank of England’s distributed ledger technology (DLT) ambitions. 

(In late 2024 it revealed plans for a pilot “digital bond” using DLT to “explore how new technology can be applied to the lifecycle of the UK’s sovereign debt issuance process” under what it is calling “DIGIT”.)

Ramsden said that the new RTGS system meant the central bank “will be consulting on whether to extend settlement hours for RTGS, perhaps in phases with the potential to enable access to settlement to near 24/7. We also want to expand further access to RTGS accounts for settlement.”

See also: UK nails the coffin shut of the “New Payments Architecture”. Now, burn it?

The RTGS facilitates the safe transfer of funds between parties. 

Settling in central bank money mitigates the risk of one party defaulting, and settling under the RTGS model prevents credit exposures between banks building up in the settlement process. (Reserves that banks hold with the Bank of England also provide a buffer against liquidity shocks.)

The Bank of England earlier said of the RTGS modernisation programme that it hopes, “enable future changes to be more efficient, less resource intensive and quicker”, allow far more organisations to open accounts with the central bank (currently some 220 have RTGS accounts and there is a lengthy queue), and allow for additional functionalities via API.

“Digitised paper, not digitised processes”

Back-end systems in financial services have lagged the trading side.

“Our technological architecture still operates on the basis of digital bond and share certificates being transferred digitally in sequence and then stored in electronic vaults, with separate ledgers needing to be separately updated and reconciled… In effect, we have digitised the paper, but we have not digitalised the process of settlement in markets,” Ramsden said. 

See also: "A humungous monster": This bank is eyeing a Sybase to MongoDB migration. First up, those stored procedures...

“While ‘front office’ functions such as electronic trading have captured much of the attention and investment, the less visible but equally critical post-trade environment has lagged behind…” he added, saying the modernised settlement engine will open up new market opportunities. 

The Bank of England is now exploring “introduction of a synchronised settlement interface to allow the RTGS platform to interoperate with other ledgers, including tokenised asset ledgers, to achieve atomic settlement… we are also embarking on a programme of wholesale experiments to test the use cases, functionalities and prospective designs of a wholesale Central Bank Digital Currency…the outcomes of which can be compared with synchronisation,” he added.

The Stack says: Well done to all involved in the process; this was not an easy change programme, we can say from a safe distance, and it is the kind of genuinely important effort for which hardly anyone ever actually gets any credit.

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