Rush Limbaugh the controversial US talk radio host and ally of former president Donald Trump, has died aged 70.

Limbaugh said a year ago that he had lung cancer. His death was announced on his radio show by his wife, Kathryn.

Unflinchingly conservative, wildly partisan, bombastically self-promoting and larger than life, Limbaugh galvanised listeners for more than 30 years with his talent for sarcastic, insult-laced commentary.

He called himself an entertainer, but his gleeful rants during his three-hour weekday radio show broadcast on nearly 600 US stations shaped the national political conversation, swaying ordinary Republicans and the direction of their party.

Blessed with a made-for-broadcasting voice, he delivered his opinions with such certainty that his followers, or “Ditto-heads”, as he dubbed them, took his words as sacred truth.

“In my heart and soul, I know I have become the intellectual engine of the conservative movement,” Limbaugh, with typical immodesty, told author Zev Chafets in the 2010 book Rush Limbaugh: An Army Of One.

Forbes magazine estimated his 2018 income at 84 million US dollars (£60 million), ranking him only behind Howard Stern among radio personalities.

Limbaugh took as a badge of honour the title “most dangerous man in America”. He said he was the “truth detector”, the “doctor of democracy”, a “lover of mankind”, a “harmless, lovable little fuzz ball” and an “all-around good guy”. He claimed he had “talent on loan from God”.

Long before Mr Trump’s rise in politics, Limbaugh was pinning insulting names on his enemies and raging against the mainstream media, accusing it of feeding the public lies. He called Democrats and others on the left communists, wackos, feminazis, liberal extremists and radicals.

When actor Michael J Fox, suffering from Parkinson’s disease, appeared in a Democratic campaign commercial, Limbaugh mocked his tremors. When a Washington advocate for the homeless killed himself, he cracked jokes. As the Aids epidemic raged in the 1980s, he made fun of those who were dying. And he called a 12-year-old Chelsea Clinton, the daughter of former US president Bill Clinton and former US secretary of state Hillary Clinton, a dog.

He suggested that the Democrats’ stand on reproductive rights would have led to the abortion of Jesus Christ. When a woman accused Duke University lacrosse players of rape, he derided her as a “ho” and when a Georgetown University law student supported expanded contraceptive coverage, he dismissed her as a “slut”. When Barack Obama was elected president in 2008, Limbaugh said flatly: “I hope he fails.”

He was frequently accused of bigotry and blatant racism for such antics as playing the song Barack The Magic Negro on his show. The lyrics, set to the tune of Puff, The Magic Dragon, describe Mr Obama as someone who “makes guilty whites feel good” and is “black, but not authentically”.

Limbaugh often enunciated the Republican platform better and more entertainingly than any party leader, becoming a Republican kingmaker whose endorsement and friendship were sought. Polls consistently found he was regarded as a voice of the party.

His idol, Ronald Reagan, wrote a letter of praise that Limbaugh proudly read on the air in 1992 that said: “You’ve become the number one voice for conservatism.”

In 1994, Limbaugh was so widely credited with the first Republican takeover of Congress in 40 years that the party made him an honorary member of the new class.

During the 2016 presidential primaries, Limbaugh said he realised early on that Mr Trump would be the nominee, and he likened the candidate’s deep connection with his supporters to his own. In a 2018 interview, he conceded Mr Trump is rude but said that is because he is “fearless and willing to fight against the things that no Republican has been willing to fight against”.

Mr Trump, for his part, heaped praise on Limbaugh, and during last year’s State of the Union speech, awarded the broadcaster the Presidential Medal of Freedom – the nation’s highest civilian honour – calling his friend “a special man beloved by millions”.

Mr Trump called into the Fox News Channel to discuss his friend’s death on Wednesday, saying they last spoke three or four days ago, lauding him as “a legend” with impeccable political instincts who “was fighting ’til the very end”.

Former president George W Bush said Limbaugh “spoke his mind as a voice for millions of Americans”.