The Conservatives push for a vote demanding the government reveal the warnings raised about Lord Mandelson's appointment as Britain's ambassador to the US.
Around 190 peers have signed up to speak during the two-day debate, which would break the previous record of 187 speakers set during the second reading of the EU withdrawal bill in 2018, if all of them contribute.
After an interview by Sky's James Matthews, he and Mark Stone both received angry messages from the embassy team. The ambassador was very unhappy with the exchange. One source said at the time: "He was furious and you guys are in the deep freeze."
Left-wing MP Bell Ribeiro-Addy has said she did not secure the nominations required to make it into the next round of Labour's deputy leadership contest.