The television presenter Duncan Stewart is reported to be in a stable condition in hospital in Belarus after he fell while filming.
Members of the Chernobyl Children's Project, who are travelling with the presenter, say his injuries are serious.
The accident happened inside the Belarussian area of the Chernobyl exclusion zone, about 200 kilometres from the capital, Minsk.
His family have said that say he is being very well looked after and the work that he was doing with the Chernobyl Children's project will continue.
Duncan Stewart's brother and son are travelling to Belarus today.