Thomas Mensforth, known as Mensi and believed to be in his 60s, died in hospital where he had bravely fought Covid for some time.
The group’s official Facebook page announced his death on Friday, December 10.
In a message, they said: “Today we lost a punk rock legend. Our hearts go out to his family, friends and everyone he inspired.”
The group had previously provided an update to fans on Monday, December 6 after a message from Mensi’s family saying he was in intensive care but was fighting every day.
He was the frontman of the Angelic Upstarts which formed at South Shields in 1977 and were hailed as one of the first street-punk groups.
Mensi and the group had a strong socialist working class and an anti-fascist philosophy.
Great days of early punk
They appeared on Top of the Pops in 1979 singing one of their greatest Teenage Warning songs.
After a brief separation, they reformed in 1988 and several times since.
The group continued to perform with Mensi, who was a huge Sunderland AFC fan, being the remaining original member.
Earlier this year, he was interviewed by Sunderland filmmaker Rob Kilburn of media company Tyne and Weird for a new documentary – Organized Chaos, due out next year – on the North East punk scene.
Rob said: “I knew Mensi, he was pretty legendary in North East punk circles.
“He played in a lot of venues in the North East and I think a lot of people saw him in their youth.
“He came across as a really genuine, really genuine person. I felt like he stood up for his values and was a bit of a working class hero.”
Hundreds of tributes have already been left on the group’s Facebook page.
One fan said: “A man of principle with convictions and a voice, you will be truly missed!”
Another described him as: “A legendary and incredible leader. I am really sorry!”
One fan sent condolences saying, “A big hug to his family, friends and the punk rock family who lost a great man today.”
Another said: “RIP Mensi… you have inspired so many and I will always be a UPSTART”.