The High Court will later consider separate legal challenges from the Lib Dems and SNP over their exclusion from ITV’s general election debate.
ITV’s head-to-head between Conservative leader Boris Johnson and Labour leader Jeremy Corbyn is on Tuesday.
The SNP and Lib Dems say it is unfair not to invite them to take part.
The Lib Dems have also sent a legal letter to the BBC over its decision not to include their leader Jo Swinson in a debate on 6 December.
The SNP said it expected the High Court to decide on Monday whether the two legal challenges should be heard together and a ruling is expected later in the day.
Speaking ahead of the hearing, SNP Westminster leader Ian Blackford, said: “This challenge is not just about the SNP, it’s about fairness for every voter and viewer across the country who have a right to see the real choice at this election on that debate stage.
“By excluding key parties from the debate, viewers are being deprived of the opportunity to make thei