A three-week-old baby who was in desperate need of a heart transplant has died, his parents have said.
Carter Cookson, who was born prematurely on Boxing Day with heart problems, had suffered three cardiac arrests and was on a life-support machine.
His parents Sarah and Chris Cookson had been running a social media appeal to find a donor.
But on Saturday they posted on Facebook that he had “gained his angel wings”.
The post from Mrs Cookson, 44, said that their “brave baby boy” Carter “could not fight anymore” and had died at 17:44 GMT.
The parents also posted on the Find a Heart for Carter Facebook page, saying: “Thank you to everyone who has helped to try and find Carter’s gift, we will be eternally grateful.”
In 2013, Mr and Mrs Cookson lost their first son, Charlie, aged two.
He died of an undiagnosed condition – unrelated to Carter’s – which caused problems with his muscles and bones and compromised his immune system.
Writing on Facebook, Mrs Cookson added: “We are heart broken….our two boys are in heaven without their Mammy and Daddy we feel so empty and our hearts will never recover.
“No more pain baby boy, No more tubes..be free with your big brother and Granda…until we can all be together again.”
Thousands of people posted their condolences on the social media site beneath a final photograph of Carter.
The Cooksons, from South Shields, South Tyneside, launched an appeal to find a new heart for Carter after being told a transplant was his only hope.
Their plea for an organ donor for Carter was shared widely on social media.
On Friday, they said doctors at Newcastle’s Freeman Hospital had advised them that time was running out.
Last week, South Shields Labour MP Emma Lewell-Buck raised the donor appeal at Prime Minister’s Questions.
Theresa May described it as a “tragic case” and highlighted the “opt-out” organ donation system due to be introduced next year.
A candlelit vigil was held for Carter outside South Shields Town Hall on Thursday evening.
Mr and Mrs Cookson launched a charity supporting families of children with life-limiting illnesses in 2013 following the death of Charlie.