By Daniel J. McLaughlin
Kate Hoey will be standing down as an MP after 30 years when the next general election is called.
The Labour MP is a controversial figure in her party, after campaigning with Nigel Farage and supporting the government over Brexit.
She has been called "a brave and principled fighter" over her stance.
However, critics say Hoey "never let the facts get in the way".
The Telegraph's Tom Harris says that Labour was once a tolerant and diverse party, but "now it treats left-wing Brexiteers like apostates". He notes that Kate Hoey is further evidence of this.
Harris calls Hoey's departure "a matter of regret" that will reinforce the notion that to be "properly" Labour, MPs must be totally committed to the European project.
He writes: Those who voted Leave in 2016 increasingly see Labour as a party that's hostile to their opinions, if not their interests.
"It's a far cry from the Labour Party of only a few years ago, when comrades could chat respectfully about their differences on a range of subjects, from nuclear weapons to nationalisation to education."
He adds that Hoey is a "useful and painful" remind that Labour was once tolerant.
Harris concludes: "Kate Hoey is an asset to the Labour Party. She has been a brave and principled fighter for what she believes, and yesterday's announcement though understandable, is regrettable. I wish her well."
The Guardian's Hannah Jane Parkinson bids farewell to Hoey, calling her "the wild Brexiteer who never let the facts get in the way".
She writes: "So long, Kate Hoey! It's been a blast. In the way that being hit by shrapnel might be. Labour's MP for Vauxhall has (finally) announced she will not stand as a candidate for the party in the next election."
She explains that Hoey was an ardent Brexiteer, while her Vauxhall constituents voted almost 78 per cent remain.
Parkinson argues: "With esteemed friends from [Nigel] Farage to [Jacob] Rees-Mogg, the pro-hunting, pro-shooting Labour MP loved a party. Just not her own."
She examines key moment from Hoey's political career, from her campaigning with Farage on Brexit to having a worse record of pro-gay rights than 120 Tory MPs.
Hoey will not seek re-election as MP for Vauxhall in the next general election. The 73-year-old has been MP for the south London constituency since a by-election in 1989. She is one of half a dozen Labour MPs who have announced they will quit.
She previously said she would not run again after the 2015 general election, but then stood when the 2017 snap election was called.
In a letter to constituents, Hoey said: "I will, of course, continue every single day to give all my help to constituents in Vauxhall and campaign for policies that make life better for residents."
She lost a no-confidence vote in her local party last year when she was accused of ignoring her constituents over Brexit. She campaigned with Nigel Farage's Grassroots Out in 2016, famously posing with the then-UKIP leader on a barge on the Thames.
The Brexiteer has voted with the government to stop a soft Brexit or remove a no-deal Brexit as an option. Hoey backed an amendment from the European Research Group, headed by Rees-Mogg, to rule out a customs border in the Irish Sea.
The next general election is not scheduled to take place until May 2022. However, a snap election could be called if there is a deadlock in parliament over a no-deal Brexit in the autumn.