They do not take a political party's whip, nor affiliate to the crossbench group, nor are they Lords Spiritual (active Church of England bishops).
Formerly, the law lords were also a separate affiliation, but their successors (justices of the Supreme Court), if peers, are disqualified from sitting in the Lords until they no longer hold a judicial position.
Peers may also be required to sit as non-affiliated while they hold certain senior positions within the Lords (e.g. the senior deputy speaker), as a means to preserve the neutrality of their official roles.
[2] A member who is elected as Lord Speaker must withdraw from any party affiliation,[3] but is not considered to be a non-affiliated peer.
Former lord speakers have sat as crossbenchers after holding office.