Ministers join pupils aiming for personal bests.
The initiative, run in partnership with the Youth Sport Trust, is using London 2012 to inspire pupils to do more sport and this year, pupils have been encouraged to pledge to achieve a personal best in an Olympic or Paralympic sport.
Mr Hunt joined Olympic gold medallists Sir Chris Hoy and Jonathan Edwards as they launched the 2011 event at Southfields Community College in London, where schoolchildren were competing in sports such as table tennis, boccia and trampolining.
Sir Chris, said: “School sport is something I am very passionate about and it was great to see such a fantastic school at Southfields Community College get involved. I was lucky in that at my school there were lots of sporting opportunities but that is not the same across all schools and that is what Lloyds TSB National School Sport Week is all about.”
Mr Robertson visited Bacons College in South London where secondary school pupils were also taking part in the opening day.
National School Sport Week is a week-long sporting celebration for primary and secondary schools across Britain held every summer.