The time available for the House(s) to object to a negative instrument if they wish. The objection period is defined in legislation as how long the House had to take action, usually 40 calendar days from when the instrument is laid and the House(s) are not in a recess of more than four days. During the objection period instruments can be withdrawn or revoked, while procedure concludes at that point it does not affect the objection period end date.
Subject to change depending on Parliamentary recesses/prorogation etc. but will be '40 days from laying"