You shouldn’t state your political preferences or say anything that compromises your impartiality. Don’t sound off about things in an openly partisan way. Don’t be seduced by the informality of social media into bringing the BBC into disrepute. Don’t criticise your colleagues. Don’t reveal confidential BBC information. Don’t surreptitiously sanitise Wikipedia pages about the BBC.
— The BBC releases its in-house social media guidelines for journalists (PDF).