I got a marketing email the other day which offered me the chance to win one of three prizes. They’re of good value – £250 – and at first sight seem to be a no-brainer to complete their survey.

When I started the survey I was – unsurprisingly – being asked for complete details of my financial history, preferences, and a range of personal data questions which would allow companies to bomb me with email, calls, and post. I know this because the conditions of the prize draw included “transfer your personal information to a member of the Group, which means our affiliated companies, including our parent holding company and its subsidiaries, located in Canada, USA, the UK and/or Latin America”

Your data is valuable and worth a lot more than £250.