Why Theresa May fears dropping her Brexit red lines

Brexiteer nerves will not be settled by Jeremy Corbyn's welcoming of 'indications' from the government that they may compromise in 'key areas'. That will be read as code for caving in on a customs union, something that is fiercely opposed by many on the front and backbenches of the Tory party. The prime minister spoke of 'additions and clarifications' to the political declaration - the shorter of the two Brexit deal documents that outlines the UK's future relationship with the EU. But non-legally binding changes may not be enough to calm a Labour leader worried about a future Brexiteer prime minister ripping up the promises of their predecessor. 'Red lines must move', said Jeremy Corbyn.