And it may seem like a controversial thing to say but the values that allow the abuse of disabled parking bays sit on the same spectrum as the values that lead to disability hate crime.

This is an emotional and empirically powerful statement, and it seems to me the kernal of your thesis repudiating alledged BNP "values". I recommend you begin your speech here.

What kind of picture of our society are we seeing where a group of people are overtly targeted for abuse by others in society?

This is an excellent introduction to a spectrum, or "picture of our society," which covert and overt injury of persons living with physical disabilitities coexist.

Mass murder is a difficult point of departure to, as it forecloses, investigation of socially acceptable hostility toward persons living with physical disabilities, covert at one extreme and overt at the other. This example belongs near the conclusion of your speech.

Which is a story about how corrupt ideology destroys good people: covert --> overt over time.

You would like to relate political objectives articulated by BNP propaganda to normative behaviors ("social attitudes") of indifference to injury of persons living with physical disabilities.

The picture will benefit from notes of public policy import in the UK, 1900-1940, that illuminate the intellectual foundations of the BNP alledged political agenda as well as institutions which would facilitate it in the event party members succeed to public office. To endemic poverty, affirmative legislation, and "hate crime" I would add development of the eugenics movement during the period.

If as wiki claims, "The limited popularity of eugenics in Britain was reflected by the fact that only two universities established courses in this field," is an appropriate measure of "social attitudes," then the BNP alledge hostility to "weak and unproductive" class must appear all the more aberrant to your audience's image of British decency.

Otherwise, a T4 event attributable to their inaction is indeed an anachronistic, nonsensical threat to its vanity and is best omitted.

Diversity is the key to economic and political evolution.