The Home Secretary took to the stage to represent the Conservatives in place of Theresa May – who had refused to appear – despite the death of her father, Tony Rudd, on Monday.
Mr Rudd, a retired stockbroker and WW2 pilot, was 93 and had planned to watch his daughter on the BBC debate on Wednesday evening.
A source told the Daily Telegraph: “The family got together on Tuesday night with all the children to celebrate their father’s life.
“Their father took such pride in her he would have loved it. He was actually looking forward to watching this debate.
“It would have been madness for her (not to take part) – it’s just not what her father would have wanted.”
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A source close to Miss Rudd added to The Sun: “It just shows how tough she is.”
Miss Rudd’s loss comes just six months after the death of her ex-husband, the Sunday Times journalist AA Gill, who died from cancer.
The former couple were married for five years in the 1990s and had two children together.
Miss Rudd appeared in Cambridge for the election debate after Mrs May refused to take part, despite Labour leader Jeremy Corbyn deciding to appear at the last minute.
She appeared alongside Corbyn, Liberal Democrat leader Tim Farron, Ukip’s Paul Nuttall, Green Party co-leader Caroline Lucas, Leanne Wood of Plaid Cymru and SNP deputy leader Angus Robertson.
Miss Rudd was widely praised for her confident performance, especially coming so soon after the death of her father.
She attacked Mr Corbyn for his “fantasy economics” and hit out at his views on the IRA and terrorist organisations.
Labour’s shadow international trade secretary praised Miss Rudd for her appearance, but criticised the Prime Minister for sending the Home Secretary in her place.
He said: “I know the pressures that are on politicians during an election campaign and the fact that she has been prepared to come and do that shows that she is an estimable woman.
“But what does it say about Theresa May that knowing that Amber had been through that, she forced her to do it rather than to come in there and stand up for herself?”
Top pic: PA