Nigel Farage is not scheduled to take part in the BBC EU referendum debate, according to UKIP. Handout / Getty

The leader of UKIP — Britain's only national pro-Brexit party — claimed on Wednesday that neither he nor any of UKIP's representatives have been invited to appear in the BBC's televised European Union referendum debate.

BBC bosses decided not to invite UKIP's Nigel Farage to represent the Leave campaign in the debate, claims The Express newspaper.

As things stand, the panel members for the June 21 debate — two days before Britons vote — are yet to be officially announced. A BBC spokesperson told Business Insider over the phone on Wednesday that talks were still ongoing regarding who will represent each side.

The BBC said that "the debate will feature senior politicians and other key figures on both sides of the argument."

The debate is set to take place in front of thousands at Wembley arena on June 21 and will be shown nationwide on the BBC1 channel.

The party told The Express that the BBC has offered Farage two other broadcast slots in the run up to June 23 instead. These two broadcast slots were reported to be in the form of an interview and an appearance in a debate for young people to be held in Glasgow, Scotland.

The UKIP leader posted the following tweets on Wednesday morning:

UKIP chairman Steve Crowther wrote to the BBC to make a formal complaint, according to the Express. The letter reads as follows:

It is widely accepted that without UKIP there would be no referendum at all. As the only nationwide political party that advocates leaving the European Union, which won the national European election in 2014 and secured close to four million votes at the general election last year, and which has its own separate and substantial campaigning allowance from the Electoral Commission, we believe that UKIP has an unassailable claim to be included on the main panel in this important debate.

The debate is set to be chaired by Question Time host David Dimbleby alongside Today’s Mishal Husain and Newsnight presenter Emily Maitlis.

It is expected to involve two teams of three speakers representing each side of the referendum divide answering questions and discussing the many issues surrounding Britain's EU membership.

The corporation has also had to reject concerns that the Wembley audience will be "hijacked" by Brexiteers, and said that the political leanings of all audience members will be thoroughly checked prior to the event.

With just six weeks to go until voting day, the campaign for Britain to leave the EU has enjoyed a steady increase in support, according to recent polls. The latest Poll of Polls from non-partisan group What UK Thinks said the "Leave" vote made up eight points on Remain in just two weeks, with the two campaigns exactly neck-and-neck.

BI contacted UKIP for an official statement on Wednesday morning.