The Lords has been a [constitutionally limited] voice of temperance and calm over the recent years of populist madness.
An unelected element to the legislature reduces the danger of the cult of populism and the damage of the necessarily short-termist goals of the elected chamber.
He’s done one here
https://www.theguardian.com/politics/2022/nov/19/keir-starmer-i-will-abolish-house-of-lords-to-restore-trust-in-politics