Talks on proposed pay cuts between representatives of front-line staff and management at the learning disabilities charity Norwood broke down after three minutes, according to the charity and the union Unite.
Staff requested the meeting after Norwood announced plans to reduce hourly pay rates for some workers and to make head office staff redundant as part of an attempt to save £3m a year.
The meeting at the charity's office in Stanmore, north-west London, last week, had been scheduled to last for two hours.
Jamie Major, the Unite regional officer accompanying the Norwood union representatives, said they left because the management refused to negotiate on several issues, including the payment of on-call staff and a minimum pay level for care workers and support workers.
He said managers had also threatened to sack staff who did not agree to sign new contracts that would cut their pay by up to 43 per cent.
The union says 50 per cent of Norwood's 1,000 staff are members of Unite.
In a statement, Norwood said: "We wish to point out that it was, in fact, the decision of Unite's regional officer to end talks prematurely, and he chose to leave the meeting, which had been scheduled to last two hours, after approximately three minutes.
"Norwood has carried out a lengthy and meaningful consultation with staff over essential cost reduction plans. We are happy to resume discussions with Unite and invite them to do so."
The charity's local authority funding, which amounts to about £20m a year and represents 75 per cent of its income, has been cut by 20 per cent.
Unite has started collecting signatures from the charity's staff, which it said it hoped to use to force the charity's management team to negotiate with front-line staff.