.
Ian Austin, MP for Dudley North, has become the ninth MP to quit Labour this week.
Mr Austin told the BBC he was quitting because the party had become a "narrow sect" under Jeremy Corbyn and had failed to tackle anti-Semitism.
But he said he had no plans to join the new Independent Group of former Labour and Tory MPs.
He said he would not call a by-election, as the Labour leadership has demanded of defectors.
Mr Austin, an MP since 2005, told BBC West Midlands: "This is the most difficult decision I've ever had to take but I've taken it because I've become ashamed of the Labour Party.
"I grew up listening to my dad, who was a refugee from the Holocaust, teaching me about the evils of hatred and prejudice.
"One of the main reasons I joined the Labour Party as a teenager here in Dudley more than 35 years ago was to fight racism and I could never have believed I would be leaving the Labour party because of racism too."
Mr Austin, a minister for regional affairs under Gordon Brown and shadow minister under Ed Miliband, said he "agreed" with the eight MPs who left Labour earlier this week that things "have got to change".
However, he wants a Brexit deal concluded, rather than a further referendum on EU membership.
The Labour leadership has called