Former Conservative Party deputy chairman Lord McAlpine has died at his home in Italy, aged 71.
Lord McAlpine was previously an aide to Prime Minister Margaret Thatcher and a highly successful fundraiser for the party.
When she left office in 1990 the peer became disillusioned with the leadership of John Major and launched a number of harsh attacks on the new leader of his party.
In 2010, the former political adviser and businessman stood down from the House of Lords to keep his non-domiciliary tax status, but retained his title.
The peer, who had three daughters, spent his final years running a bed and breakfast near Puglia with his third wife Athena.
His family said in a statement: "It is with great sadness that the family of Lord McAlpine announce his peaceful death last night at his home in Italy."
Lord McAlpine was wrongly implicated in a child abuse scandal in 2012, when allegations were contained in a BBC Newsnight investigation.
The claims led to the corporation's then-director general George Entwistle quitting his job less than two months into the role. Mr Entwistle said he had to take "ultimate responsibility" for the broadcast.
The BBC was forced into making an apology after abuse victim Steve Messham admitted that the man who abused him in the 1970s and 1980s was not Lord McAlpine.
Mr Messham told the BBC he had been abused by a senior Tory from the Thatcher era at a north Wales children's home when he was a teenager. This led to fierce online speculation as to the identity of the politician, and the peer was incorrectly accused of being a paedophile.
Solicitors for Lord McAlpine said they were ready to sue for defamation, arguing his reputation had been left in "tatters" as a result of the programme.
Lord McAlpine later received damages from a number of internet users, including the wife of the House of Commons speaker John Bercow, after libellous messages were posted on Twitter.
Ms Bercow agreed to pay £15,000 in damages for her "innocent face" tweet. Comedian Alan Davies paid damages after he reposted a tweet which linked the peer's name to a television report about a "senior political figure who is a paedophile".
The BBC Trust investigated the broadcast and found that members of the team responsible failed to follow the corporation's editorial guidelines.
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