BBC journalists picket outside Television Centre earlier this monthCredit: Danny Lawson/PA
Radio 4's Today programme began an hour late this morning, at 7am, preceded from 6am by two short documentaries, and a stripped-down version of BBC 1's Breakfast was broadcast in place of the usual programme, although it was fronted by regular presenter Charlie Stayt.
The shortened Today programme also aired with its usual presenter, John Humphreys.
BBC Radio 4's World at One will also be replaced, with a news summary and repeat of a programme about soul music in its place.
The industrial action by members of the National Union of Journalists follows a previous 24-hour walkout on 15 July.
The strike is a reaction to proposed job cuts at the World Service and BBC Monitoring, where a total of 387 planned job cuts include 100 compulsory redundancies.
There have been four compulsory redundancies so far at the World Service.
Staff out on strike include star BBC reporters, including business editor Robert Peston and the political editor, Nick Robinson.
Michelle Stanistreet, the NUJ's general secretary, said: "The BBC's current actions spell disaster for quality journalism, the corporation is wasting thousands of pounds making hard working, skilled and experienced journalists redundant. Instead they should be adopting alternative solutions and redeploy those who are threatened. No one should be forced out of work when there are jobs available for journalists to do.
"By taking strike action members intend to show they are prepared to stand up for colleagues under threat and the union is calling on the corporation to step back from the brink and avoid further industrial action in response to compulsory redundancies at the BBC."
Stanistreet said that the NUJ expected around 3,000 staff to take part in today's strike, with picket lines due to form up and down the country. Pickets are scheduled for 9am at Television Centre and Bush House, the offices of the World Service.
The union is due to meet with BBC management on 11 August to hold talks over the proposed redundancies.
Prior to the previous strike, on 15 July, the union accused the BBC of avoiding talks which it claimed "could have averted the stoppage".
A BBC spokesman said: "We are disappointed that the NUJ has gone ahead with today's strike and apologise to our audience for any disruption to services. Industrial action does not alter the fact that the BBC is faced with a number of potential compulsory redundancies following significant cuts to the central Government grants that support the World Service and BBC Monitoring.
"We will continue with our efforts to reduce the need for compulsory redundancies, however, the number of posts that we are having to close means that unfortunately it is likely to be impossible for us to avoid some compulsory redundancies."
Lucy Adams, the BBC's director of business operations, said in a message to staff that the corporation could not agree to the unions demands for no compulsory redundancies.
"Following the cuts in central Government grants to the World Service and BBC Monitoring we have had to close 387 posts, meaning that regrettably there are nearly 100 staff who as a result are facing compulsory redundancy. We have been working with all these affected staff to ensure that they have opportunities for redeployment and retraining but we cannot and will not give preferential treatment to individuals depending on their union status.
"We hope the NUJ will realise that these issues are best solved at a local level, and a national strike that penalises all our audiences is not in the interests of their members, other BBC staff or licence fee payers."
Today's strike will be followed by an indefinite work to rule, which begins tomorrow.