It's not legally required but I think if it's removed it can only be bad.
The MoT "computer" stores advisors and will flag up a previous issue if it's not been addressed next time round (apparently).
For example your car passes but has minor wear in various bushes, corroded brake lines and failing shocks.
A tester may pass the vehicle and just advise bt next year all those will almost certainly be failures . . . .
So your car that's fine now (just because it has a test certificate) will be a lemon come next test.
Be careful !!