On Tuesday, July 17, Hoey joined Frank Field, John Mann, Graham Stringer and Kelvin Hopkins in rebelling against Labour whips in Parliament and voting with the government on the Brexit trade bill.
Former Labour MP Austin Mitchell described them in a tweet as the "fabulous five" but they have been targeted by Remainers and Corbynites who say they are out of line and should be deselected.
Hoey, 72, has been the MP for Vauxhall, a constituency in south London which is one of Labour's safest seats, since 1989.
Born into a Protestant, Unionist family in Northern Ireland she has often held views which were out of kilter with the rest of the Labour Party.
Supporter of Fox Hunting, Smoking And Handguns
Her support for the Protestant, Unionist majority in Northern Ireland was often at loggerheads with Labour — which was traditionally allied with the Catholic, Irish nationalist SDLP in Northern Ireland — and she also spoke out in favor of fox hunting, which was outlawed by Tony Blair's Labour government.
But Brexit is the issue which has found her out.
She represents Vauxhall — a constituency only a few miles south of the Houses of Parliament — where 77.6 percent of voters opted for Remain in the 2016 Brexit referendum.
Hoey though, has always been staunchly pro-Brexit, and her decision to back the government this week has triggered a furious reaction in her local Labour Party.
Next week the Vauxhall Constituency Labour Party will debate a motion which calls for Hoey to be censured, suspended by the Parliamentary Labour Party and declared ineligible for reselection as a candidate at the next General Election.
'Reprehensible Collaboration'
The motion called her "collaboration" to be "reprehensible" and said it undermined the Good Friday Agreement by preventing options to rule out a hard border with the Irish Republic.
In an article on the Labour List website, Vauxhall Labour activist Jamie Green, wrote that Hoey had been a problem for the party for several years.
"While many of us oppose her views on Brexit, fox-hunting and the Ireland question, we've tried to tolerate and believe the best of Kate given her principled stance on the Iraq war, which ended her ministerial career, and her hard-working reputation in the local community. But the 2016 referendum and her decision to campaign with the likes of Nigel Farage left a bitter taste in the mouths of activists and has led us down a slippery slope. Deselection seems to be the only option left," wrote Mr. Green.
He said she had put her wish for a hard Tory Brexit above her constituents.
Hoey was never an ordinary Labour MP.
She grew up in Northern Ireland and was pretty much the only person from an Ulster unionist background to be a Marxist.
Controversially Selected in 1989
She failed to get elected as a Labour Party in Dulwich at the 1983 and 1987 general elections but in 1989 she was controversially chosen by the Labour Party ahead of Martha Osamor — a black activist who had won eight nominations to Hoey's one.
Under Tony Blair, Hoey climbed up the greasy pole of politics, becoming Minister for Sport in 1999 but falling out of favor in 2001 and voting against the invasion of Iraq in 2003.
She opposed the ban on handguns after the Dunblane massacre and also voted against the introduction of a smoking ban in pubs.
Ironically Kate Osamor — whose mother Hoey controversially replaced as Labour's candidate in Vauxhall in 1989 — is now the Labour MP for Edmonton in north London.