The Liberal Democrats have lost a High Court challenge to demand Jo Swinson be invited to tomorrow's head to head TV debate.
The Lib Dems and SNP brought a joint challenge against ITV over its decision to exclude their party leaders from the televised election debate.
Two leading judges ruled there was "no arguable breach of the Broadcasting Code".
Lord Justice Davis, sitting with Mr Justice Warby, said: "The clear conclusion of both members of this court is that, viewed overall, these claims are not realistically arguable.
"It follows that the television debate scheduled for tomorrow evening between the leader of the Conservative Party and the leader of the Labour Party may lawfully go ahead."
ITV is hosting a head-to-head debate between Boris Johnson and Jeremy Corbyn on Tuesday, which will not include any other party leaders.
Lib Dem representatives lodged papers at the court in London last week and said it was "vital for our democracy" to have both sides of the Brexit debate included in TV debates during the election campaign.
And Scottish First Minister Ms Sturgeon said last week that it is "fundamentally unfair" for other parties to be cut out of the debate.
Sky News has proposed a November 28 date for its debate, while the BBC has confirmed it will host two debates, on November 29 and December 6, in addition to a series of Question Time specials.