BBC journalists strike over job losses
Picket lines were mounted outside studios across the country and union officials said the action, which began at midnight, was being "solidly supported."
Journalists are angry at around 100 compulsory job losses at the World Service and Monitoring division, which monitors mass media worldwide, as the broadcaster seeks to make huge savings.
The World Service announced in January it was cutting 650 jobs as the government withdrew funding as part of an austerity drive, under which the BBC is seeking to cut its budget by 16 percent in the next few years.
Today`s strike caused the broadcaster`s main Today news programme on Radio 4 to start an hour behind schedule at 7:00 am (0600 GMT), while the main BBC TV evening current affairs programme Newsnight will not air.
"All the indications are that the strike is being solidly supported, and members of other unions have refused to cross picket lines, so morale is high," said Michelle Stanistreet, general secretary of the National Union of Journalists (NUJ).
A BBC spokesman said, "There are in excess of 100 BBC posts for which compulsory redundancy is regrettably unavoidable, and this is our focus, regardless of whether staff are members of unions." A statement from the broadcaster added, "We are disappointed that the NUJ has gone ahead with today`s strike and apologise to our audience for any disruption to services.