Deputy Prime Minister Nick Clegg traded the commons for the classroom when he faced a panel of students from Carshalton School for Girls.
Mr Clegg was in the Sutton to announce his parental guarantee plan.
The policy would mean pupils in all types of secondary education are taught from the same curriculum by qualified teachers.
Academies and free schools are exempt from having to adhere to those standards.
The Deputy Prime Minister was accompanied by Carshalton and Wallington MP Tom Brake, and Schools Minister David Laws MP this afternoon.
The 11 girls on the panel ranging from year groups nine to 13, asked Mr Clegg what his plans were for a greener Britain.
He replied: "We need a level playing field, where building green infrastructure is as affordable as using fossil fuels.
"In the past low-carbon options have been more expensive.
"What we need is diverse sources for green energy, including things like offshore wind farms."
The girls also asked what his favourite food is and what animal he would like to be. Mr Clegg said his favourite food is mango and he would like to be an albatross.
When he asked how England will get on in the World Cup he said: "We are going to walk it."