i would say yes they can, read the declaration you signed on the VAF4 form.
I understand that UK Border Agency (or a trusted third party) may make reasonable checks to confirm the accuracy and authenticity of evidence I have
provided and documents I have submitted with this application. I further understand that UK Border Agency (or a trusted third party) may also make
reasonable checks on any sponsors to my application to verify statements contained in the application and establish that I will comply or have complied
with the terms of any visa granted.
also i've seen on a TV program where they british embassy in India phoned the bank of someone who was applying for a visa to confirm their details and balance.
i know the taxman uses credit agencies..
