Bournville village was built 45 years after Cadbury's shop opened
A member of the Cadbury dynasty has said new firm Kraft has a "duty" to look after its new workers.
Sir Adrian Cadbury called the propsed takeover by US food firm Kraft "a tragedy" and said he hoped they would look after the workers.
Birmingham City Council has asked the chocolate maker's shareholders to reject the takeover bit.
And the Bournville Trust has reassured people living in the village and in Shropshire they will not be affected.
The trust, a housing association with 8,000 homes across the West Midlands including a village at Lightmoor, in Telford, said George Cadbury had ensured the trust's independence when he set it up in 1900.
Sir Adrian Cadbury, a former chairman of the firm, said his message to Kraft was "quite clear".
"If this goes through you have a duty.
"You will have taken on a great business which has been built on the quality of the people who have been working for it.
"You have a duty to look after these people," he said.
Cadbury shareholders have until 2 February to back the deal.
Councillor Neville Summerfield, cabinet member for regeneration at Birmingham City Council, said the proposed takeover would be a "terrible blow" for the city, particularly in light of other losses such as LDV.
The van maker went into administration in October with its assets later sold to a Chinese firm.
"There is much at stake in the next couple of weeks not just for Birmingham, but also for an iconic symbol of British industry and through it the industrial future of the entire country," Mr Summerfield said.
Cadbury has plants at Keynsham in Somerset, Marlbrook in Herefordshire and in Chirk, Wales.