I'm not sure if you are being deliberately obtuse or not.
A red cross does not just appear from nowhere, there are earlier signs on overhead gantries advising a lane ahead is closed (not once have I suggested otherwise or mentioned barriers or cones or any other method of traffic calming etc.)...
That's what you are supposed to do - merge in turn by taking up all the available space in the lanes up to the closure.
https://www.autoexpress.co.uk/car-news/105986/70-per-cent-of-drivers-don-t-know-how-to-merge-in-turn