Diabetics and insulin suppliers are increasing their stocks of insulin. They want to avoid possible shortages if Britain leaves the European Union without a deal.

David Burns is a 37 year old teacher, who lives in London. David is one of 3.7 million diabetics in the UK who rely on insulin to regulate their blood sugar levels.

David: "All of these come from Switzerland, these come from Denmark, but we don't make any of this here and none of these companies that made this are British - I think the vast majority of them are Swiss."

A no deal Brexit will mean replacing customs agreements and health controls. This could delay drug imports and risk patients' lives. The Department of Health says it has plans to fast-track emergency medicine deliveries by sea and by air if there are delays at the border. But David is still concerned.

David: "If I ran out of insulin, obviously I don't want to test this out, but I can't imagine I'd have more than a couple of months left on this planet, so I'm terrified of a no-deal Brexit."