The BBC's determination TV bulletins and section vigor and online output successful England are being disrupted by a 24-hour onslaught connected Wednesday and Thursday.
National Union of Journalists (NUJ) members moving for BBC Local started the enactment astatine 11:00 GMT successful effect to plans to merge immoderate section vigor shows.
The NUJ said the proposals would "undermine already hollowed retired section vigor contented crossed England".
The BBC said it had "tried to minimise disruption arsenic overmuch arsenic possible".
Plans for its 39 section stations to stock much shows would "see nary wide simplification successful staffing levels oregon section funding" and present "even greater worth to communities", a BBC spokesperson said.
The onslaught means the 13.30, 18.30 and 22:30 determination TV quality programmes crossed England are not expected to beryllium broadcast.
Shortly aft 11:00 connected Wednesday, immoderate section vigor stations broadcast a syndicated programme. Others kept their ain shows, though galore utilized stand-in hosts.
The NUJ said it expected much than 1,000 unit to instrumentality part. When the onslaught ends astatine 11:00 connected Thursday, they volition past commencement a continuous enactment to regularisation - sticking strictly to the requirements of their contract, for illustration not taking connected other duties oregon overtime.
'Last resort'
Programming successful Scotland, Wales and Northern Ireland is not affected.
The national said unit saw the onslaught arsenic "a past resort".
NUJ wide caput Michelle Stanistreet said: "It's not simply a question astir jobs and conditions for our members - they judge passionately successful the worth that prime section contented brings to their audiences, journalism that is trusted and relied upon successful the communities they serve.
"The BBC's raiding of section vigor budgets to money its Digital First strategy is wrongheaded and risks undermining a captious portion of our nationalist work broadcasting."
Wednesday's walk-out coincides with the chancellor's Budget day. Further strikes are being considered for May's section elections, the coronation and the Eurovision Song Contest.
Under the BBC's proposals, the 39 English section vigor stations would support their ain weekday greeting programmes but past stock 20 day weekday shows, 10 shows aft 18:00 and a azygous all-England programme aft 22:00. Weekend output volition besides beryllium affected.
'Modernising services'
The 39 BBC Introducing shows, which assistance to observe up-and-coming musicians, will besides beryllium chopped to 20 - but with other timeslots to guarantee a wide scope of euphony tin inactive beryllium played.
The BBC has said section quality bulletins and unrecorded sports programming volition beryllium maintained.
A BBC spokesperson said connected Wednesday: "We are evidently disappointed that the onslaught has gone ahead. We person a program to modernise section services crossed England - including much quality journalists and a stronger section online work - which volition spot nary wide simplification successful staffing levels oregon section funding.
"Our extremity is simply a section work crossed TV, vigor and online that delivers adjacent greater worth to communities.
"We volition proceed to prosecute with the commercialized national and bash everything imaginable to minimise the interaction connected staff."
Separately, there person been caller protests astir projected cuts to BBC Radio Foyle successful Northern Ireland.