Disability

It does. But it can also be an advantage. When people are willing to vote on a single issue. Bigger parties fear the loss of votes more than in a proportional system.

Green never got a huge % of votes. 2MPs is the highest number (I think). But long before they had any MPs, larger parties adopted the issue rather than lose votes.

And that one I won't advertise. Forced and won a referendum with 0 MPs. I may hate their cause. But they were able to effect politics with way less votes. Than disability advocates both able and disabled exist.

I hate FPTP as far as its ability to represent the desires of a democratic society. But for single issues. It actually can help smaller populations gain a voice.

EDIT: I honestly think just forming a serious party would raise enough publicity. That the 3 big parties would panic. Despite Tories recent pre-election attack on disabled, Most voters really only notice the issues when they see it with family members. Having a couple of elections where a party is running while pointing out the broken promises plus challenging past negative attacks from political parties. Can you really see either the Tories or Labour openly disagreeing with a rational argument on this? Their options in n election will be to lie, deny intent to harm. Or ignore us.

There really is no shortage of data that can be used to gain support. And our own population alone is all we would need to scare the larger parties away from ignoring such a party.

The hardest part would be raising the money to get started. The community has no shortage of able/skilled voices. It's convincing them to fight for an agreed platform that would be difficult.