She received the award of a bronze statue of a rat up a drainpipe, the favourite phrase of political journalist Anthony Bevins who died in 2001, at a ceremony in London last night.
It is the second major journalism prize in a week for Sambrook, who won the Paul Foot Award last week. Both awards recognised Sambrook's work online, including articles published on the openDemocracy website.
Sambrook's work has led the End Child Detention Now campaign, for which she has produced a range of investigative reports and research for various publications and given some of her work away for free to promote the campaign. She told Journalism.co.uk after her Paul Foot win that her campaigning journalism and investigations had been personally "financially catastrophic".
"Anthony Bevins set a terrific example of journalism keeping a distance from power finding his own stories with tenacity and a sense of mischief. I am stunned to find my name linked to his. This is especially welcome at a time when the government has completely reneged on its commitment to end child detention," Sambrook said yesterday in a statement.
Commenting on Sambrook's win, editor of the UK section of openDemocracy, Anthony Barnett said it showed the growing importance of the web to investigative journalism: "Journalism is going to be improved by the web, as shown by Clare's brilliant writing and sharp and brave reporting. She knows that an outsider with a mind of her own, supported by the team at End Child Detention Now' can produce really effective reporting of the highest standards."