Scottish independence: How the BBC reports polling day
Strict rules mean the BBC, like other broadcasters, isn't allowed to report details of campaigning while the polls are open.
In all national elections, the BBC is legally required both by its own charter and electoral law to adopt a code of practice.
The BBC Trust adopts an equivalent approach for national referendums and publishes guidelines for all BBC output to supplement its normal editorial guidelines in the very specific circumstances of an election or referendum period.
The basic principle behind this is the need for due impartiality of political coverage, as set out in the agreement accompanying the BBC Charter.
This requires the BBC over time to "give due weight and prominence to all the main strands of argument and to all the main parties."
So, on polling day specifically, the BBC (like other broadcasters, though they are covered by the Ofcom code rather than a charter) doesn't report on the campaigns or the issues which have been debated in them.
Coverage is limited to uncontroversial factual accounts of things like the logistics of voting, how the count will be done, or just the weather, so the BBC's output can't be seen as influencing the ballot while the polls are open.