Elisabeth Buggins, the chair of the UK Organ Donation Taskforce, has urged people to discuss their intentions for their organs with loved ones.
She told ITV News presenter James Mates that talking about the issue helps to avoid grief stricken decisions which can burden families at times of death.
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The hashtag #RoomForManchester was being widely shared.
Witnesses reported hearing a "huge bang" at the venue during the concert on Monday evening.
ITV News travels to Britain's eastern-most city to gauge how the electorate will be casting its votes.