A notice posted in the staffroom of the company-owned restaurant in Manchester's Trafford Centre shopping complex threatened staff with disciplinary action if they spoke any language other than English at any time.
It announced: "Attention All Staff. Due to the common language within the store, all staff members must use English at all times. This is in accordance to HQ".
As one-third of the staff come from ethnic minorities, they complained to local politician Qassim Afzal, a Liberal Democrat.
He brought the case to the attention of the Commission for Racial Equality, which is now investigating.
"This poster was written and displayed by a junior manager at this particular restaurant. The wording was unapproved and we recognise may have appeared insensitive. It has since been taken down," the company said in response.
McDonald's, which has a multi-ethnic workforce, explained that "staff are encouraged to speak English when working and when liaising with customers.
"Outside of these times, such as in the staffroom and on breaks, we of course respect their right to converse in whichever language they choose."
by Angela Frewin
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