Sir Keir Starmer faces the prospect of a second rebellion among his MPs over a ceasefire in Gaza, with a government intervention threatening to expose Labour divisions.
The Labour leader had attempted to see off a revolt by tabling a Commons amendment, which for the first time backed an immediate ceasefire in the Israel-Hamas conflict.
However, parliamentary procedure means it may not be debated, potentially forcing his MPs to back a motion put down by the Scottish National Party (SNP).