The BBC’s centenary celebrations season could be hit by strike action from corporation journalists concerned about plans to close the BBC News channel. Scrutiny has intensified over the proposal announced earlier this year to merge the UK rolling news TV channel and its global commercial stablemate BBC World News into a new, combined service called BBC News. The Guardian has learned that the leader of the Trades Union Congress has written to BBC director general Tim Davie to express concerns that closing the existing BBC News channel “would substantially reduce newsgathering and airtime for domestic stories” and affect UK democracy. It echoes fears of some BBC union members who have taken part in a consultative ballot that resulted in a vote in favour of industrial action. According to sources there was a strong turnout for the vote, which could now lead to a full ballot – a potential threat to the BBC’s coverage of its 100th anniversary in October. The proposed BBC channel closures and subsequent loss of 70 jobs form part of a £500m cost-cutting and redistribution mission by Davie to create a “digital-first” organisation and help achieve cuts of £285m a year necessitated by the government freezing the licence fee for two years. Davie is due to visit news channel staff on Friday but corporation insiders are concerned the director general does not realise the on-screen impact of the proposals. The new BBC News will show news for international and British audiences, with adverts only shown abroad and a UK “opt out” stream to cover big domestic stories, using reporters and a breaking news team, that will simulcast BBC Breakfast, BBC One bulletins, Newsnight and a visual version of Radio 5 live presenter Nicky Campbell’s show. A BBC spokesperson said: “Our teams are rightly proud of the work they’re doing, and times of change are always difficult, but we need to ensure better value for licence fee payers and stop the duplication that currently exists with two parallel channels.” However, one insider claimed a BBC senior manager told staff there is “low ambition” for UK breaking news and questioned why, as management admit channels are being closed, regulator Ofcom is not stepping in. The TUC’s general secretary Frances O’Grady said in her letter to Davie: “News reporting is already increasingly desk-based, and news content increasingly filled with interviews with guests with a political agenda. The plans appear likely to further these trends, with limited resources for sourcing stories from communities and workplaces, for investigative journalism, and for specialist correspondents.” She said the TUC “appreciate the pressures” the BBC is under due to the licence fee being frozen but said “high-quality news coverage is at the very heart of the BBC’s most important public service duties” and is “vital” to the “quality of UK media [and] UK democracy”. O’Grady also said the arrival of new rival services such as GB News and Rupert Murdoch’s Talk TV “makes it even more important that the BBC continues to provide a national service of high-quality, impartial reporting”. On Wednesday GB News appeared to be gearing up to fill domestic news gaps the new BBC News might leave, with a shake-up of its daytime schedule to focus more on rolling news, with the departure of some presenters and new programmes GB Newsday and GB News Live.