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.
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A man, reportedly armed with a knife and a baseball bat, was detained close to the event and police cleared the area as a precaution.
A remarkably mild night
Thousands of people have gathered in the centre of Manchester for a vigil in the wake of the terror attack.