Applications made before 31 March will be valid for 90 days, while afterwards the bank’s GI products will only be available direct.
A Santander spokesperson said: “Santander reviews its product propositions and channels to ensure they continue to deliver value for customers.
“Following a review Santander for intermediaries has taken the strategic decision to focus on its mortgage proposition for its intermediary partners.
“Santander will continue to offer general insurance products through its branch network, over the phone and online.”
Santander added that customers with an existing Santander Additions policy – its name for its GI product range – will continue to be protected under the terms of their existing contract.
Kevin Paterson, managing director of The Source, said: “Santander are taking the decision to focus on what they’re best at – leaving specialists to fill the gap.”
Simon Burgess, managing director of British Money, said: “It doesn’t come as any surprise as banks are under pressure, as intermediaries are under scrutiny to make sure they are doing the best for their clients.
“They have to gravitate towards decent policies and that’s not what’s on offer from Santander. It’s a brave intermediary who doesn’t sell the best policy to their client.
“Santanders GI offering is of a very poor quality with heavily laden commissions. It’s difficult for an intermediary to sell standard dross.”