Tony Blair was quizzed about global warming by pupils as part of a BBC project involving more than 100 schools across the UK.
The prime minister told the children, who visited Downing Street for School Report News Day, that the government was doing all it could to tackle climate change.
Other political leaders, including the Conservatives' David Cameron and the Liberal Democrats' Menzies Campbell were also interviewed, as were pop star Lil' Chris and John Challis, who plays Boycie in Only Fools and Horses.
As well as questioning VIPs, the thousands of 12- and 13-year-olds taking part also reported on the issues that affect them on a daily basis, including bullying, crime and transport.
During their meeting with Mr Blair, pupils from Coventry also raised the issues of Iraq, education and what the prime minister plans to do after he retires.
Pardeep, 13, felt Mr Blair answered honestly and was "very approachable and talkative".
Pupils also raised the issue of global warming with David Cameron and went on to question him about poverty.
Among the tough questions facing Sir Menzies Campbell, 65, was: "Are you too old for the job?"
For those pupils without big interviews lined-up, popular topics included government plans to raise the school leaving age to 18, healthy eating, the row over size-zero models and crime and gang culture.
Ellie Crisell said School Report was an opportunity for the BBC
Other schools looked at the 200th anniversary of the abolition of the slavery act.
Lois, 13, from Eltham Hill Technology College for Girls in London, reported how she is herself descended from slaves.
A pupil at Chatham South School in Kent who helped secure half-price bus fares for pupils made the front page of its School Report website.
And students at Lewisham City Learning Centre hosted a live weather forecast and predicted a chilly end to the week.
Schools from the Outer Hebrides to Jersey learned how make TV, radio and online news stories for School Report and had to work to a strict deadline.
Since September 2006, students have been training to become journalists, with support from BBC staff and resources on the School Report website.
The BBC, which sent reporters to many schools to cover events and act as mentors, aims to link to their reports and bulletins, generating a UK-wide audience for their work.
Huw Edwards, who presents on BBC News 24 and BBC One and is a former teacher, said: "The project allows students to develop literacy and editorial skills through all kinds of new approaches."
Presenter Ellie Crisell, from BBC News 24 and Newsround, hosted live updates from a cluster of schools in Manchester for School Report.
She said it gave the BBC "an insight into how 12- and 13-year-olds view the world around them, what kind of stories are important to them, and what they want from news".
BBC Director General Mark Thompson said the BBC hoped it would make all the students taking part "think about journalism, media and the big issues of the day in a new way".