The moment Nick Clegg and his wife had to tell their eldest son he had blood cancer was one of the "toughest things" for the family, Miriam Gonzalez Durantez has said.
The former deputy prime minister and Ms Gonzalez Durantez told ITV's Lorraine Kelly how their son Antonio, now 15, was diagnosed with Hodgkin lymphoma in September last year.
He found a small, painless lump in his neck and tests found he also had lymphoma across his chest.
After receiving treatment on the NHS at University College Hospital in London, including four monthly cycles of chemotherapy and heavy steroids, he is in remission having suffered severe side effects including hair loss, vomiting and fatigue.
Mr Clegg said his son is on the road to recovery:
He added the couple's other children, Alberto and Miguel, had taken the news well.
"Once they heard from us that he will be OK, again they are just so, so practical - just 'OK then'," he said.
The couple are raising awareness of the charity Bloodwise, which is launching a report urging more research into less toxic treatments for children with cancer.
The charity said blood cancer is the most common among children and young people, with more than 1,100 of those under 24 diagnosed in the UK every year.
Dr Alasdair Rankin, director of research at Bloodwise, said: