Metropolitan Police Commander Stephen Clayman, who is the national lead for knife crime, said it is sometimes harder to buy paracetamol than it is to buy a knife.
Collectively the new measures will be known as Ronan's Law, in memory of 16-year-old Ronan Kanda who was stabbed to death in Wolverhampton in 2022 in a case of mistaken identity.
His mother Pooja Kanda told Sky News: "What a legacy to have in my son's name.
Tougher prison sentences will be introduced for selling knives to under-18s and retailers will be obliged to report suspicious or bulk purchases of knives that could then be sold on via social media.
It is easier for children to buy knives than it is to purchase paracetamol a police review has concluded.
