When the GDPR was first talked about it was often characterised as being about stopping "nasty companies" using your personal data in ways you didn't want them to. It was rare to hear people talk about the use of personal data by political parties. Now the ICO feels the need to send out a letter to the parties reminding them that data protection law applies to them during the GE campaign. 

The quote below from former a Cambridge Analytica employee is a timely reminder that the power of data can be used for political as well as commercial purposes. Maybe my former life as a political journalist and my present one as a privacy practitioner aren't as far apart as I used to think.