Lloyds TSB has outsourced intrusion detection services to Unisys in a two-year deal worth an estimated $2.6m (£1.6m).
The financial services giant said that security staff resourcing and training issues played a major role in the decision to consider alternatives to expanding its in-house service.
Lloyds TSB does not expect to make any savings through the move, which it described as cash neutral.
The outsourced service will be delivered from a Unisys facility in Amsterdam supported by a security command centre at Unisys' headquarters in Blue Bell in the US.
It will use applications from ISS RealSecure, Lloyds TSB's chosen software supplier, to scan and deal with threats to its systems.
Bob Spencer, head of group IT security and risk at Lloyds TSB, told vnunet.com that concerns about the growing threats facing the financial services sector had prompted a review of operations.
"As more services enter the electronic world, and as internet banking becomes more prevalent, threat levels can rise," he explained.
"We have to be aware of those threats and do as much as possible to protect ourselves.
"The prospect of having shifts of 24/7 staff and retraining and retention issues led us to look at a whole list of managed service providers."
But Spencer admitted that the outsourcing option is no cheaper than running the service in-house.
The cost will come out of Lloyds TSB's security investment portfolio, which is separate from the company's IT budget.
"I think it's important to have a separate budget for security," said Spencer. "Intrusion detection is an immature technology and there were challenges to overcome, but there was a recognised need to do this."
The in-house staff who ran the financial company's intrusion detection service have been retained to manage the relationship with Unisys.
The managed service is due to go live over the next couple of weeks, and a formal review will be completed after six months during which time Spencer expects a fair amount of fine tuning to take place.
He is confident that the investment will pay off and help the bank provide the best levels of service to its 16 million customers. But Spencer admitted that "the proof will be in the pudding".
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