endorsement of the prime minister

Technically Starmer didn’t endorse him. IIRC his statement was something like “I don’t think that I’m actually allowed to endorse a member of another party” or something along those lines.

searches

theguardian.com/…/clacton-byelection-likely-to-be…

The prime minister, Keir Starmer, even addressed his candidacy on the sidelines of the Nato summit. “I think it’s actually against Labour party rules to endorse another [candidate],” he said.