Bose's arrival as senior government relations and public policy manager marks an expansion of the bank's government relations team.
His is one of two new roles in the strengthened set-up, with Alejandra de Villota set to join later this month from Santander’s Brussels office as government relations & public policy manager.
Both will report to Sam Hinton-Smith, who heads the team after the departure of Emmeline Owens for MHP.
Hinton-Smith joined the bank last year after previously working at Nomura and John Lewis.
He said: "We are significantly building and developing our government relations and public policy function to ensure that we communicate effectively with policymakers.
"It is vital that government and political stakeholders understand our business and its contribution to the British economy as we transform Santander UK into a relationship-focused retail and commercial bank."
The team, which also includes Daniel Rosenstone, is responsible for Santander UK’s interaction with government and political audiences, and the bank’s engagement on UK public policy issues.
The expansion was overseen by Jennifer Scardino, director of comms, public policy and CSR.