How do you mean? Amber is the one you stop on unless it's unsafe to do so. It doesn't matter a jot how the long the sequence is, as soon as that's amber that means you should be ready to stop unless you really can't.
People keep going however, and treat it like " ah you've a few seconds til you have to stop" and 4-5 cars squeeze on through. In reality, only that first car should ever be in a position that it has to proceed through an amber light because it is close to the stop line.
You stop on amber. Simple as. It's written in very plain english in the Road Traffic Act.
For Amber, you stop unless unsafe to do so.
Same pretty much goes for red.
Once you are within a Junction on Amber or Red, the lights are of no significance to you. Right of Way is yours regardless of where the Green Signals are.
All in the road traffic acts.