The announcement has triggered a leadership contest that could see Andy Burnham as the next PM.
Tom Hayes, Labour MP for Bournemouth East, said: “I backed the Prime Minister to the last, and his decisions are lifting children out of poverty, getting NHS care to people faster, and keeping us safer in the world.
“Bournemouth East is benefiting from a Labour Government.”
Cllr Patrick Canavan, leader of the Labour group on BCP Council, said: “I am devastated by the decision of Keir Starmer to resign as leader of the Labour Party.
“Keir took the Labour Party from its worst defeat in 2019 and the moral bankruptcy of antisemitism to changing the Labour Party and winning a landslide majority.
“I am confident that history will look back on him with far more respect than some of his colleagues have shown him.”
Neil Duncan-Jordan, Poole MP, told the Press Association: “I’ve been calling for Keir Starmer to go since November last year and periodically since then so I’m pleased that he’s gone today, I think it’s the right thing. He did it in a dignified way.
“I don’t think his resignation means that the Labour Party is finished by any means.
“In fact, I think this is our chance to rebuild and in particular to gain the trust of the British public again.”
Jessica Toale, Bournemouth West MP, said: “I am sorry to see that Keir Starmer has resigned as prime minister. His resignation statement was honest and dignified.
“It was testament to his character and of the seriousness with which he has always approached public service.
“Keir Starmer took a Labour Party that many believed was unelectable and transformed it into a government capable of winning a landslide general election.”
Vikki Slade, Mid Dorset and North Poole MP, said: “It is in no one’s interest to keep changing prime minister, but it was clear that Starmer’s time was up.
“I hope that this process happens quickly and that we can move the country forward so that we have a stronger, safer society that stands proud on the international stage and works for us all.”
Ian Girling, Dorset Chamber Chief Executive, said: “Many in the business community will not be disappointed, or surprised, to see Keir Starmer go.
“The imposition of additional taxes and regulation on employers during his time on office has been incredibly damaging, and now business face even more uncertainty with his resignation.
“It is critical that there is an orderly handover of power that provides stability and minimises any economic disruption over the coming weeks and months.”