The bank said today it had also contributed more than 10,000 hours of support from employees for the charities in addition to the funds, which will be shared equally between the two organisations.
Activities carried out by Santander staff included 120 employees travelling to help vulnerable communities in South Africa, Nepal and Cambodia, It’s a Knockout-style competitions and "Store Wars" challenges in which staff took over Age UK and Barnardo’s charity shops and competed for sales during the day.
Santander said teams of employees also ran workshops in communities on topics including digital skills, fraud awareness and financial capability as part of the partnership, which ran until the end of 2018.
The company also funded two strategic programmes that helped the charities support more than 5,300 older people to plan for the future and provide more than 1,500 hours of one-to-one support for young people around finding work.
Javed Kahn, chief executive of Barnardo’s, said Santander staff had "thrown themselves into this fundraising partnership".
Steph Harland, chief executive of Age UK, said the company’s support had enabled Age UK to support thousands of older people facing the most difficult challenges of later life.
Keith Moor, chief marketing officer of Santander UK, said he was proud of what the partnership had achieved. "By working together we were able to support the communities we live and work in and help some of the UK’s most vulnerable people," he said.
A spokeswoman for Santander said an announcement on a new charity partner was imminent.