Both the Prime Minister and Labour leader Jeremy Corbyn turned down the invitation to take part in the debate on ITV.
Ms Sturgeon, Liberal Democrat leader Tim Farron, Ukip’s Paul Nuttall, Plaid Cymru’s Leanne Wood and Green co-leader Caroline Lucas took part, with the Ukip leader finding himself under attack from all sides over Brexit.
Ms Wood used her opening statement to say: “I have a message for the Prime Minister, who I’m sure is watching tonight. You may be too scared to come here tonight, for your U-turns to be highlighted, for your cruel policies to be exposed.
“You want this election to only be about Brexit because that means you avoid talking about the real issues like the NHS, the economy and the cuts you have made to our public services.
“That’s weak leadership - weak and unstable.
“I hope all of us here tonight will show you that real leadership means being willing to defend what you stand for, not hide from it.”
The First Minister kept up the attack, saying: “Theresa May may not have had the guts to be here tonight, but her spokesperson in the form of Paul Nuttall certainly appears to be here in her place.”