Ousted WPP supremo Sir Martin Sorrell is at it again, unleashing on the company he formerly owned in a stinging rebuke.

In an interview with the UK’s Financial News, the 74-year-old questioned WPP’s direction and apparent largesse.

Once again his successor, newly minted WPP CEO Mark Read, came in for special mention, Sorrell saying he’d made some “terrible mistakes” since taking the reins of the world’s biggest media company in September last year.

“As a shareholder, it’s worrying. I don’t think there is a strong direction [for the company],” said Sorrell in the interview. “The people running WPP see their jobs as a burden now. When they get up in the morning, they feel burdened. I know that to be the case.”

Sorrell was particularly critical of Read’s decision to consolidate the business by merging agencies and selling off underperforming parts of the business in a move that was set to save £300 million ($A550 million) over the next three years.

“If you make a £300 million provision, that means you pretty much insulate yourself for 2019. The acid test for WPP will be in 2020, because that’s when the provisions will run out,” Sorrell said.

On Read’s decision to merge  J Walter Thompson with Wunderman in November, Sorrell said: “People are saying, ‘Now we know what the W is in WPP – it’s Wunderman’. That’s because a lot of Wunderman people seem to have been promoted. There is a feeling of sycophancy and that friends are being elevated rather than the more talented people.”

Sorrell’s attack is the latest in a tit-for-tat war between himself and WPP. In response to his constant belittlingly, WPP executives had claimed they felt “liberated” since his departure 13 months ago and had welcomed Read’s approach that was more “collaborative and inclusive”.

Sorrell had been accused of being too authoritarian during his time at the helm of WPP, alongside grievances over the lavish salaries and bonuses he paid himself.

WPP has not commented on Sorrell’s latest savaging but had previously said, “The new leadership is focused on WPP’s clients and people and their success, on behalf of all our shareholders.”

However, one WPP exec prepared to publicly rebuke Sorrell has been Johnny Hornby, CEO of the WPP-backed The & Partnership.

Hornby telling the Financial News: “I find it odd that Martin doesn’t concentrate on his own firm [S4Capital].

“I don’t know where the phrase ‘mind your own business’ comes from, but it feels relevant in this regard because I think he should let Mark get on and run the business,” Hornby said.