ACI Worldwide says it authorised 10.7 million card transactions for the UK's Royal Bank of Scotland Group (RBS) on 23 December 2002, breaking all previous processing records for the bank.
ACI's Base24 system, which supports RSB's card processing service Streamline, authorised the transactions at a peak of 318 transactions per second.
The vendor says activity for the month was 20% up on last year when the same system authorised 8.6m transactions, peaking at 271 transactions per second.
Jim Tomaney, ACI worldwide marketing director, Emea, says despite concerns about the economy and consumer confidence, UK card transactions continue to rise.
"This is the 13th consecutive year that ACI has seen a record rise in single day transaction volumes around the Christmas period," he says.