Labour deputy leader Tom Watson said he had a "duty" to inform the British public about sex abuse allegations made against former home secretary Leon Brittan. Watson conceded though that he was wrong to describe Brittan as "close to evil".

Brittan's brother Sir Samuel Brittan called on Watson to apologise after police dropped an inquiry into rape accusations made against Brittan, who served as home secretary under Maragret Thatcher and died in January, aged 75.

In a blog for the Huffington Post, Watson said he was sorry for the "distress" Brittain's family experienced. He said he had been told of "multiple accusations" of abuse against Brittan. He conceded he "did not and could not know if they were true" but said he thought they should be "fully investigated".

Former Home Secretary Sir Leon Brittan
Before his death Sir Leon Brittan strongly denied allegations he was involved in a child sex ring Reuters

"As the tributes flowed in from his lifelong friends, I felt for those people who claimed he abused them," he said.

"The choice facing anyone who is presented with testimony of this kind is whether to pass it on to the authorities and urge them to investigate or to ignore it. I chose the first option. I felt it was my duty to do so."

In July, 2013, the Crown Prosecution Service found that there was insufficient evidence to prosecute Brittan for allegedly raping a 19-year-old female student in 1967. Watson subsequently called for a full review of all rape allegations made against Brittan.

Following a letter to the Director of Public Prosecutions by Watson, Police subsequently interviewed Brittan when he was dying of cancer, but did not press charges. Earlier this week, a vulnerable man who made sex abuse allegations against politicians – including Lord Brittan – told the BBC that he "went along with" names that were initially suggested as a joke.

Former chancellor Norman Lamont said that police investigations into historical abuse allegations risked becoming a "witch hunt."

Writing in the Telegraph, he said: "I visited Lord Brittan several times in his last days and saw the suffering of a man under the shadow of the vilest accusations. This was an extremely painful time for his wife."