I travel through here every night returning to the Rossendale Valley. I am continually baulked by drivers trying to cut in to left lane at the last possible second. Although good, legal fun can be had by staying in left lane and continuing to Rawtenstall and trapping a late cutter on the A682, requiring a 6 mile detour!
The option suggested of making the "straight on" A682 a "right turn" is the perfect answer. But making a right turn off a dual carriageway must be too radical a move for the Highways Agency. Similar things work perfectly well in the USA - though I did fall victim to it once!!