Nigel Farage is the most synonymous individual in the world on the issue of a British Exit Referendum.  He is the leader of UKIP, the party most identified with gaining this referendum for the UK and the issue of the UK's membership of the EU.

The debate would lack credibility if he were not present.  To exclude him would weaken the Leave case. He is an excellent debater,  with a consistent view on leaving the EU and an expert on this subject.  

UKIP is the party with the most UK seats in the European Parliament. To not have a representative of this party on the panel shows contempt for the electorate.

This debate is likely to be the most influential television broadcast on the issue and held just two days before the actual vote takes place.