Yellowhammer is a codename used by the Government relating to no-deal planning.
The Sunday Times reported in August that Yellowhammer documents outlined scenarios including that Britain would be hit with a three-month "meltdown" at its ports if it leaves without a deal.
The newspaper warned of a hard Irish border and shortages of food and medicine, and a senior Whitehall source told the paper: "This is not Project Fear - this is the most realistic assessment of what the public face with no deal. These are likely, basic, reasonable scenarios - not the worst case."
- How did the Government react to the revelations being made public?
The Government sought to play down the documents, with Business Minister Kwasi Kwarteng dismissing them as "scaremongering", while Michael Gove - the Cabinet minister responsible for no-deal planning - insisted Yellowhammer represented a "worst-case scenario".