What does it mean when the speaker says unlock?

Related questions

1. What percentage of voters voted for Brexit?
2. How many constituencies voted remain?
3. What percentage of the UK voted for Brexit?
4. How many Scottish voted to leave the EU?
5. What percentage of the electorate voted to leave the EU?
6. How many constituencies voted to leave the EU?
7. Is extension of Article 50 legal?
8. How did MPs vote on Brexit?
9. Will Brexit be good for the UK economy?
10. How many Londoners voted for Brexit?

Tags

1. #counted
2. #unlocked
3. #members
4. #remaining
5. #until
6. #doors
7. #lobby
8. #result
9. #announced
10. #normally
11. #paper
12. #chairman
13. #another
14. #ballot
15. #member
16. #votes
17. #house
18. #speaker