MSPs continue to debate 'Scotland's Choice' before parliament votes on whether to seek a second independence referendum at decision time.
MPs are holding a debate on Yemen. Peers are examining the Criminal Finances Bill. The Defence Committee is taking evidence on the US and Nato.
The Public Accounts Committee discusses Natural Resources Wales' annual accounts. Plenary begins with Questions to the First Minister. There is also a Stage 3 Debate on the land transaction tax bill.
MLAs hold a special meeting of the Northern Ireland Assembly to mark the death of Martin McGuinness.
Parliamentarians will get on with the day-to-day business of democracy, while remembering those affected by terrorist attack on Westminster.