In the new M1 South lane off the A50 junction near us he wanted me to brake or move over to let him into the LH lane - but far too late for that to be an option. So he cut up the van behind me, overtook in a 50 limit at about 80 (I was not dawdling) carved between two other cars, jumped a red light onto the M1 J24 roundabout and appeared to be heading off towards the Kegworth exit - suggesting that he knew all along that he had been in the wrong lane.
I was in a hurry, Grant.