A national newspaper columnist has vowed to carry out charity work to the value of STG25,000 ($A36,544) to make amends for wrongly naming Lord McAlpine as a pedophile on Twitter.
Guardian journalist George Monbiot announced today that he has agreed the "unprecedented settlement" with the former Tory politician's legal team.
In a statement on his website, Mr Monbiot said: "I have met with Andrew Reid of RMPI LLP, Lord McAlpine's representatives, and they have suggested what is, as far as I can discover, an unprecedented settlement.
"They would like me to carry out, over the next three years, work on behalf of three charities of my choice whose value amounts to STG25,000.
"I accepted the suggestion immediately and without reservation. I feel the proposed settlement reflects very well on Lord McAlpine, who is seeking nothing for himself, but wants to see work done which could be of great benefit to others."
Mr Monbiot, who currently has nearly 65,000 Twitter followers and said he had more than 55,000 when he made the false claims on the microblogging site in November, added that he was looking to work with children's and environmental charities.
Lord McAlpine announced last month that he was dropping defamation claims against Twitter users with fewer than 500 followers who wrongly named him as a pedophile, instead asking for a charitable donation.
A spokesman for the peer said: "Lord McAlpine welcomes George Monbiot's statement and settlement relating to his defamatory tweets and is pleased to have reached a settlement whereby a number of charities will benefit from these defamatory actions.
"This is a ground-breaking settlement which underlines the danger of the misuse of the internet."
Lord McAlpine was mistakenly implicated by Newsnight's November 2 broadcast in a pedophile ring which targeted children at a care home in Wrexham. His name was then widely mentioned on the internet, including Twitter.
He reached a 185,000 settlement with the BBC after it broadcast the botched Newsnight investigation, as well as receiving 125,000 from ITV and Phillip Schofield relating to a This Morning program broadcast on November 8.
He is also pursuing Sally Bercow, wife of Commons Speaker John Bercow, over comments she made on Twitter.