Data from Twitter shows that Nigel Farage scored the highest peak in social media traffic - his comments during the immigration session sparked 4,231 tweets per minute.
Ms Sturgeon won 28 per cent backing, followed by Nigel Farage (20 per cent), David Cameron (18 per cent), Ed Miliband (15 per cent), Nick Clegg (10 per cent), Natalie Bennett (five per cent) and Leanne Wood (four per cent).
In closing statements, Ms Sturgeon said: “Tonight the choice at this election has been clear: you can vote for the same old parties and get the same old politics - more cuts and more misguided priorities; or you can vote for something different, better and more progressive.”
In her closing statement, Ms Bennett tried to persuade those considering a vote for the Greens that it would not be “wasted” saying: “If you want change, you have to vote for it,” she said.
“I say vote for what you believe in. You don’t have to go on voting for the lesser of two evils. That’s how we ended up with the tired, failed politics that we have now.”
Mr Clegg thanked the audience and viewers “for sitting through this two-hour political marathon”, adding: “When you vote, make sure you do what is right for you and your family, make sure that you do what’s right for our country, but above all make sure that we don’t lurch this way or that.”
Mr Farage said in his final statement that the other leaders had shown they were “all the same”.
“What you have seen tonight is the politically correct political class. They are very keen to be popular on the international stage. They don’t understand the thoughts, hopes and aspirations of ordinary people in this country. What we represent in Ukip is plain-spoken patriotism. We believe in this country, we believe in its people, we think Britain can be a lot better than this.”
Mr Miliband declared: “I believe that it is when working people succeed that Britain succeeds. If you believe that too, I ask for your support and let’s bring the change that Britain needs.”
Ms Wood said: “Austerity is not inevitable; it is a choice. For a stronger, more prosperous, greener Wales. For a Wales that counts. For a devolution and financial settlement that is no longer second rate, give your vote to Plaid Cymru. For Wales to be strong - like Scotland - Plaid Cymru must be strong.”
Mr Cameron had the last word in the debate, telling voters: “This is an amazing country and we are on our way back. There’s a fundamental choice at this election. Stick with the plan, and with the team who brought that plan, because it’s working and it’s helping.”
Here are some of the high and low points for the seven party leaders during the live TV debate:
High: The Lib Dem leader wasted no time in distancing himself from his coalition partner, David Cameron, by starting the debate with an attack on the Tories’ tax plans. He told the audience: “Remarkably, the Conservative Party have said they are not going to ask the richest in the society to make a single extra penny of contribution to balancing the books through the tax system.”
Low: During a 2010 debate the phrase “I agree with Nick” became popular with Gordon Brown. But Mr Clegg’s policies were not as popular tonight and he did not appear to have any friends among the other leaders.
High: The Plaid Cymru leader delivered a killer blow to Nigel Farage, chiding him “You ought to be ashamed of yourself” when he complained about foreigners with HIV receiving free treatment on the NHS. She warned him that his comments were “dangerous” and “dividing communities”, earning her the first round of a applause from the audience.
Low: Pollsters ComRes ITV News had just 2% believing Ms Wood was the best performer in the two-hour debate.
High: The Ukip leader earned a chuckle from the studio audience when he rounded on Mr Cameron after he claimed Britain should renegotiate with the EU. Mr Farage said: “Mrs (Angela) Merkel, who is the real boss in Europe as we all know, has made it perfectly clear we can negotiate lots of things over the next couple of years but we cannot renegotiate the free movement of people.”
Low: He was the first to lose his temper while the leaders discussed the deficit. As they argued over how to “balance the books” he turned red, threw his arms up by his head and cried: “What’s going on here? Can we get real please?”
High: He told the audience to be fearful of the NHS under Labour, warning them: “There’s only one group of politicians anywhere in this United Kingdom who have cut the NHS in the last five years and that was the Labour Party in Wales. So when you hear Ed Miliband’s promises, think about that.”
Low: The Tory leader was challenged by Green Party leader Natalie Bennett over why Britain has not taken more Syrian refugees - an issue on which the Prime Minister has faced strong criticism in the past. She told him: “The UN has asked us very loudly and clearly to take our share of the most vulnerable.”
High: When she claimed there is nothing Nigel Farage would not blame on foreigners, the Ukip leader’s expression suggested she might have a point.
Low: No obvious lows. She was the best performer according to a YouGov poll, so perhaps she will be disappointed if she reflects that there could have been a victory for the Yes vote in the Scottish independence referendum if she had become SNP leader earlier.
High: Ed Miliband smirked and laughed his way through Cameron’s argument on the EU - telling him: “David, I’m wondering what world you live in.” The Prime Minister responded with a meek “What?” before Miliband blasted him for his weak negotiating in Europe and criticised him for “marginalising” the UK.
Low: The Labour leader suffered a clear defeat when the debate turned to zero-hour contracts and David Cameron pointed out that “about 70 Labour MPs employ people on zero-hour contracts”. To cheers and applause, he sneered at Labour for “not getting to the part that they practise what they preach”.
High: The Green Party leader did not appear to suffer a recurrence of the ‘brain fade’’ which blighted her famous ‘’excruciating’’ radio interview on LBC Radio.
Low: She was cut off as she got to her key message in declaring “we have to stop trashing our planet” in answer to a question about whether Britain’s young people have an optimistic future.