DASHCAM - Driver of Thames Water van changes lanes without looking, nearly causing a crash.

Driver of Registration FG61 LDJ needs to look before attempting to change lanes!

Coming off J9 of the M27 going onto the A27 heading towards Fareham, at around 17:55, Thames Water van driver indicated, then stopped indicating, then pulled in directly in front of me, despite the fact there was no space to do so! I had to brake hard at which point I sounded my horn. This momentarily seemed to stop the driver making the manoeuvre but then he CARRIED ON forcing his way into the lane I was in despite my flashing my lights at him. Really poor driving and, had I not been paying attention, would have caused an accident had I not braked and sounded my horn.