Paul Dacre has agreed to a new contract as editor of the Daily Mail, the chairman of the Daily Mail & General Trust has revealed.

In a rare interview with Tatler magazine, Viscount Rothermere quashed suggestions that Dacre would depart the editor's chair soon after his 65th birthday on 14 November.

"Paul Dacre is not stepping down as editor of the Daily Mail, where he is still doing a brilliant job – indeed, he has just agreed to a new contract," he said.

Dacre, who has edited the Daily Mail since 1992 and took home £1.79m last year, is employed on a rolling one-year contract which was due to expire on his birthday next month.

It is not clear when the new contract was agreed – a spokeswoman for DMGT declined to comment – but Rothermere's disclosure will answer rumours about Dacre's near-term future at the title.

The famously media-shy proprietor was also drawn on speculation that Geordie Greig, the Mail on Sunday editor, was being lined up as the successor to Dacre.

"When the time comes for Paul to hang up his hat from day-to-day editing of the Mail, I think that Geordie is definitely a contender," he said in the November issue of Tatler, which will be available on Thursday.

"He's proven himself as a magazine and newspaper man and he is definitely in the frame. But I am fortunate that, in my company, there are many strong contenders."

According to Tatler, Greig flatly denied that his potential future editorship of the Daily Mail had been discussed – "Do not believe the rumours," he said – and declined to say whether he would want the job if it became available.

Rothermere said of Greig: "He's a very bright and he's an excellent journalist and he's his own man. He's the right choice and he's done a good job, so Paul Dacre and I made the right call."

The assurance about Dacre's future comes amid a growing swell of hostility towards the Daily Mail over its controversial article on Ed Milband's late father, which described the prominent socialist as "the man who hated Britain".

A visibly angry Miliband took to television studios on Tuesday to express his fury that the newspaper had refused to apologise over Saturday's article.

"I was appalled when I read the Daily Mail on Saturday and saw them saying that he hated Britain. It's a lie," he said. "I'm even more appalled that they repeated that lie today and have gone further and described my father's legacy as 'evil'. Evil is a word reserved for particular cases and I was not willing to let that stand."

The Daily Mail is standing by the article, which it republished on Tuesday alongside a 1,000-word editorial that set out its refusal to apologise.

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