A worker at a call centre for NHS 111 handlers has claimed space at one office had been "maxed out" due to new recruits.
The worker at Sitel Group, which helps to provide NHS England's 111 service, claimed that some staff had been given only around an hour's training.
Break rooms were crowded and bins were overflowing, the anonymous worker said.
Sitel Group said it was following guidelines and has "increased cleaning measures".
Speaking on condition of anonymity, the employee at one of Sitel's two sites in Stratford-upon-Avon said there were no gloves, masks or wipes left, just disinfectant and kitchen roll for an office of about 60 seats.
"The agents are seated within arm's reach of one another," they said.
"When asking for support and advice, agents walk straight up to each other or lean over each other to point at computer screens or the phone."
Colleagues were coming in to work despite the conditions because they needed the money, they added.
In a statement, the firm said its UK sites remained open to continue supplying support to key public services and essential business.
Sitel said all of its agents "continue to receive training in line with the guidance of the clients we serve".
"We have directed all sites to follow stricter social distancing practices in line with recent government directives and increased cleaning measures to ensure our teams, including those with key and essential workers status, have every resource available to continue serving communities in the safest manner possible."
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