Britain voted to leave the European Union nearly three years ago, and 'Tonight' has been covering the Brexit process every step of the way, from the referendum campaign and the result, right through the negotiations to the recent deadlock. Allegra Stratton examines how we got here and what should happen next.

For 20 years Tonight has been investigating moments that changed Britain. In a special film, Tonight looks back at some of the biggest stories over the past two decades.