Dr Hilary Jones explained on Daybreak how Mark Cahill's hand transplant was a world first.
He said hand transplants have been done since the 1960s, however this is the first time that the hand has been removed and the donor organ has been transplanted on at the same time.
More top news
Sunshine in short supply
Samples from 95 buildings in 32 local authority areas have failed fire safety tests - 100% of the cladding samples submitted.
But which member of the royal family spends the most?