In 2011, 12-year-old Oliver died when his heart stopped during a school swimming lesson. He had an undiagnosed heart condition.
His father Mark King started the Oliver King Foundation and campaigned for all schools in England to have defibrillators.
With help from some of Oliver’s school friends and former footballer Jamie Carragher, Mr King’s mission succeeded.
Now the rollout has started, with the life saving devices being distributed to state schools who don’t already have one.
According to the Department for Education, 20,000 defibrillators will be delivered to almost 18,000 state-funded schools by the end of the academic year.
Mr King spoke to BBC Breakfast about the milestone.