A 24-hour strike among technical staff at the BBC has been "very successful", union Bectu has claimed, though the BBC said it had been "business as normal".
Bectu's strike is over changes to working patterns for some staff
Nearly 100 employees walked out over rota patterns, "all of our membership" in one area, Bectu's Tony Lennon said.
A BBC spokeswoman claimed 61% of staff in the "affected" sections were at work on Wednesday but acknowledged the BBC could not tell who was a union member.
The action was timed specifically to target the State Opening of Parliament.
"We're hoping there will be some disruption to news operations today," said Mr Lennon.
"We hope the managers, who we know are covering the work of some of our striking members, will not be able to cope with some of the complicated faults which can happen in news."
Bectu members were striking over "changes in their scheduling patterns which could cut their pay by up to 20% and could mean they work up to 30 days more per year", he added.
The BBC said that at 2230 GMT on Tuesday, 61% of people "who were scheduled on the rota and expected in" were striking.
That number had dropped to 39% by 1030 GMT on Wednesday, the spokeswoman said.
"The BBC has no way of knowing who is a member of the union and who is not.
"It's difficult to know how Bectu came to their figure of 100%."
The standard of Tuesday evening's 10 O'Clock News on BBC One and Newsnight on BBC Two had been "fairly consistent with what it would normally be", she added.