Umbrella company registration without permission?

Simple question really.

Is it legal for an agency to register a new temporary worker with an umbrella company without first getting permission from the temporary worker ?

Bear in mind that in order to register an employee with an umbrella company they need to pass on personal information including bank details ec’t.

I should make it clear that I’m talking about a temporary worker who’s registered with an agency and done a couple of weeks work for them before finding out that the pay will be through an umbrella company.

when they sign up with the agency, they probably sign some paperwork that has some small print regarding passing information to third parties.
it makes it all nice and legal as far as data protection is concerned.

I`m not suprised they are in this position. Afterall how many people actually read the small print of the paperwork thats shoved in front of them?