Liberal Democrats are taking advice on a legal challenge if TV companies try to freeze out Jo Swinson from leaders’ debates in the coming general election campaign.
Ms Swinson issued a warning at the Lib Dems’ annual conference in Bournemouth that it would not be “responsible” for broadcasters to stage head-to-head showdowns between Boris Johnson and Jeremy Corbyn only.
And The Independent understands that the party has already started talking to lawyers about routes to challenge any format which presents the snap election as a straight battle between Conservatives and Labour.
Discussions have already begun between broadcasters and parties over a possible series of live debates in the run-up to the election expected in November or December.
No format proposals have yet been made public, but Lib Dems fear that Ms Swinson may be invited only onto large panels featuring leaders of smaller parties, where it will be more difficult for her to make the case that her party is the main choice for most voters wanting to stop Brexit.
The party is understood to be pushing for three-way debates, though it is not thought to object to the inclusion of the Brexit Party's Nigel Farage in a four-sided clash between the parties currently making a mark in national polls.
One Lib Dem insider said: “There is no way we are going to stand by and allow debates to go ahead between Corbyn and Johnson that don’t feature Jo Swinson.
“We are taking on the two old parties and beat them both in the European elections, won hundreds of seats off them in the local elections, and have been rising in the polls through the year.
“We know Labour and the Tories will try and do everything they can to keep Jo from the debates – she is a threat to both of them – but we are not going to let that happen.
“We’re taking legal advice and looking at every option to make sure that our candidate for Prime Minister is given the same airtime as the old party leaders – they are both proposing Brexit and we will fight to make sure the voice for Remainers is heard”
Ms Swinson insists that the Lib Dems – who currently have 18 MPs at Westminster – are fighting to secure a parliamentary majority and put her into Downing Street, where she promises to halt Brexit "on day one".
She said that any TV debate should not give the impression that the election is a choice between Johnson and Corbyn, with no explicitly anti-Brexit voice on offer.
Broadcasters need to “take and consider very seriously the responsibility they have in making that decision because politics is uncertain”, said the Lib Dem leader.
“We have seen unpredictable results in other parts of the world and broadcasters need to make sure that people who are voting in those elections get the chance to see and hear from the people who might be their next prime minister.
“To freeze out somebody who is in that position would not be a responsible cause of action.”
It is not yet clear whether debates will take place ahead of the election.
The televised battles between major party leaders first became a feature of UK politics in the 2010 election, but subsequent campaigns have witnessed a variety of formats amid tussles over which leaders are willing to appear.
Sky News has been running a Make Debates Happen campaign, and gathered more than 143,000 signatures on a petition demanding the creation of an independent commission to ensure they become a regular fixture of future elections.
A BBC spokesperson said: “In any future election the BBC will ensure that its audiences have the chance to hear from representatives from the main political parties”.