Approaching from the South, there is cycle only access across Handford Road to continue North along Portman Road (shown in the photo) which allows access, amongst other things, to the new crossing of Norwich Road at Barrack Corner.
However, the lights allow motor traffic to turn left or right (not straight on) on a green signal which creates significant risk of conflict and left-hooks for cycles going straight on.
Unless cyclists take a strong position at the junction in the centre of the lane there is a risk of left-hooks from cars turning left.
This is made worse by the fact that there is a marked cycle lane and ASL which tends to encourage cyclists into a dangerous position at the left hand side of the road.
It is possible to avoid this by leaving Portman Road and using the Toucan crossing to cross Handford Road, but this isn't mandatory for cycles and the "No Entry except Cycles" signage suggests that using the on-road route is the most obvious option.
This issue could be partially resolved by an advance "cycle only" filter phase on the traffic lights, but other than that I can't see any more effective solution than a sign which makes it clear how the road layout works (i.e. that cars may turn left or right, but that cycles may be proceeding straight on).