I think there is the fear , rightly so of 'Wage Compression' at the bottom at the scaleThe reason RMT asks for an underpin (aka minimum uplift) is that percentage increases gradually increase the gap between the highest paid and lowest paid. The underpin is an attempt to stop that gap from widening too far. I'm not sure why higher grade members object to that (if what @Signal_Box says is really the reason that it has been turned down)
if you look at the NHS 'Agenda for Change' (AfC) pay scale , compared to it's introduction in in the mid 2000s , band 1 is not closed ( and residual band 1 staff are on the same as band 2 ) Band 2 now only has a single pay point which is the adult NMW/NLW ( or in some places a higher RLW (real living wage) of 12.00gbp/hr rate)
the lower pay point in Band 3 is a few pence an hour more than the NMW/ NLW or in some trusts the RLW and there is only one further pay point in band 3
band 4 now only has 2 pay points
This demonstrates significant pay compression compared to the past.
Pay scales for 2023/24 [Historical]
NHS terms and conditions annual, hourly and HCAS pay values scales for 2023/24