Piers Morgan has become embroiled in a savage Twitter spat with Good Morning Britain replacement Alastair Campbell over mental health campaigning.

The 56-year-old former GMB star brutally mocked his 63-year-old temporary replacement when the latter got the wrong end of the stick during an online exchange.

Former Labour spin doctor Alastair has been drafted in to replace Piers this week – months after the loudmouth star quit GMB following an argument over the believability of Meghan Markle ’s Oprah Winfrey interview in March.

Alastair – who has taken Piers’s old seat beside 50-year-old Susanna Reid – has been highlighting mental health work during his time on the show.

Piers Morgan brutally mocked Alastair Campbell in a Twitter exchange

On Tuesday, Piers took to Twitter to question if celebrities cash in on mental health campaigns as it is a frequent topic of conversation for stars to spotlight on social media, TV and interviews.

Questioning the validity of some celeb mental health charity endorsements, Piers asked: “I’m curious to know just how much money famous ‘mental health campaigners’ are making from constantly preaching about it & exploiting their myriad ‘problems’ - and what percentage of that money they give to mental health charities.”

He added: “Celebrity victimhood is a lucrative business.”

Alastair has joined Good Morning Britain as Piers' replacement

Taking issue with the tweet, and assuming it was a personal attack, Alastair hit back at his GMB predecessor.

He tweeted: “If you mean me @piersmorgan - @schooltruth and I have a charity account which takes a share of my earnings, which go to causes we believe in, mainly mental health and education for poorer children.

“I do paid speaking gigs and often ask for fees to be paid to charity.”

But Piers denied Alastair had been the inspiration for his Twitter comment, brutally hitting back: “No, I was talking about celebrities..”

Seemingly admitting defeat, Alastair replied: “Ah ok!”

Alastair Campbell has proved a controversial choice to replace Piers, with many objecting to the ex-Labour spin doctor due to his involvement in the Tony Blair government’s decision to take the UK to war in Iraq based on lies.

Piers himself mocked the decision in a recent Daily Mail opinion piece, writing: “Forgive me for having a wry chuckle at the fact that I had to leave the show for declining to apologise for disbelieving Princess Pinocchio’s porky-pies, only to now be replaced by someone who has never apologised for spinning us into an illegal war that cost more than a million lives."