Two bus companies are to close, leaving thousands of people without local services in West and South Yorkshire.
CT Plus and Powell's - both operated by transport social enterprise HCT Group - will cease running services from Friday and Monday respectively.
The companies cover routes in Leeds, Wakefield, Huddersfield and Halifax and in Sheffield, Rotherham and Barnsley.
HCT Group cited rising fuel and labour costs as well as the pandemic as the reasons for the decision.
In a statement, it said: "Everyone at CT Plus Yorkshire and Powell's - and across the wider HCT Group - has worked tirelessly to put the operations in Yorkshire on a sustainable footing, but there is nothing further to be done and the situation cannot continue.
"We want to ensure services to the public are not disrupted, but most importantly we want to preserve as many jobs as possible.
"We are now talking to commissioners across Yorkshire, seeing if we can transfer as many services as possible to new operators."
It said it was an "immensely sad day" for the group but hoped new operators would be found within the week.
Stagecoach has already confirmed it will take over some services in South Yorkshire, and Arriva has done the same in West Yorkshire.
West Yorkshire Mayor Tracy Brabin said her thoughts were with the drivers and staff who were now without employment, but feared this was "only the start" of closures.
"Bus patronage hasn't risen as quickly as we'd like after the pandemic, which is why I and others have been calling on government to extend its Bus Recovery Grant beyond October," she said.
"Smaller operators need that support to help them through this difficult time, they don't have multi-national parent companies to fall back on."
The South Yorkshire Mayoral Combined Authority said in a statement it was "co-ordinating with local authorities and other bus companies to put alternative services in place, where possible".
'How will I manage?'
Katie Howson, 32, lives in Pudsey and fears losing the 81 service will leave her having to pay up to £20 a day in taxi fares.
She said: "I use it at least four times a day, to get my little girl to school, then I jump on it back home because I start work at 9.15.
"Then I get it again at 2.30 to collect my baby from nursery and do the school run, so it is really going to affect me."
She added: "Last year there was a lot of issues with it not turning up, then we got letters to say it would be improving.
"Every single day there are several mums who use it to get to school and a lot of elderly people use it too. If it doesn't come back in time for school, I don't know how I'm going to manage."
In West Yorkshire, the services affected are: 30, 61, 61A, 81, 81A, 113, 341, 354, 355, 374, 375, 377 and 378.
The 113 Dewsbury and District Hospital-Pinderfields Hospital-Pontefract Hospital will now be operated by Arriva Yorkshire.
In South Yorkshire, 19 services are affected, all of which run from the Powell's depot in Hellaby, which employs about 50 staff.
The services are: DR1, 49, 521, 18, 637, 638, 639, 3, 117, A1, X20, 5, 6, 10, 10A, 35A, 61, 62, 201 and X20.
Stagecoach has confirmed it will take over some of the services in South Yorkshire, including service 6 from Sheffield to Millhouses, the 61/62 service between Hillsborough and Low Bradfield and the 201 service from Chapeltown to Stocksbridge.
The company said customers with valid Powell's bus tickets can continue to use them on the replacement Stagecoach services, and on other routes previously covered by Powell's, until 14 August.