How much data do you give away on the tube?

Passengers on the London underground give away data about their movements every time they tap in and out of a ticket barrier.

Transport for London uses these millions of bits of data to help understand how the network works and to keep the system flowing smoothly.

Jane Wakefield went along to see how the Bond Street station upgrades are going and to find out how TfL intends to use this data in future.

BBC News