Video: The changes Williams made to make its car legal
Williams will start the Australian Grand Prix weekend having made enforced changes to its 2019 Formula 1 car from testing to ensure the legality of the FW42.
The FIA is understood to have been unhappy with two elements of William's design - its wing mirrors and part of its suspension - and the team has modified these as a result to ensure it has no issues at this weekend's season opener.
Technical editor Jake Boxall-Legge joins Glenn Freeman to explain why there were potential issues with the original designs of the two components.
The F1 drivers facing unusually unfair challenges in 2019
Liberty urged to use midfield fight as 2021 F1 template