CLEAN : Farage calls for honest argument from Cameron on EU

The speaker discusses the current momentum of a political movement with eight days remaining, emphasizing the importance of hearing the Prime Minister's positive arguments for the European Union. The speaker expresses a desire for honest debate rather than negative rhetoric and highlights their personal commitment to the cause, having fought for 25 years for this moment.

What does the speaker mean by 'an endless series of negative empty threats'?

What significance does the speaker attribute to the last 25 years?