Cadbury's parent company, Mondelez, bought back the licence from fellow confectionery company Burton's Biscuits to produce some of the UK's best-loved snacks.
Previously, Cadbury Fingers were produced under a licence by Burton's at its factory in Edinburgh alongside other lines made by the biscuit giant such as Maryland cookies and Royal Edinburgh Shortbread.
And the move by Mondelez – previously known as Kraft – has sparked concerns production may be stopped in Edinburgh and taken outside of Britain.
After the shock closure of Cadbury's Somerdale factory near Bristol in 2010, unions and shadow ministers are concerned job cuts could be on the cards.
“Mondelez has a history of broken promises - and we have no idea what their commitment is to production in the UK, said Eamon O’Hearn, a GMB National officer.
“They need to come out and tell us exactly what their plans are for our members working for Burton’s making Cadbury's biscuits."
However, somewhat confusingly, Cadbury's owners refuted that the notion that a decision about jobs was its problem. A spokesperson for Mondelez said:
While Burton’s sold its Cadbury licence to Mondelez earlier this year, Burton’s continues to make Cadbury-branded biscuits. They continue to be produced in Burton’s factories by their employees under a co-manufacturing agreement.
Cadbury was bought by US food giant Kraft in 2010 in an £11.5bn deal, having been an ever-present constituent of the FTSE 100 since the index's inception in the mid-1980s.
Although Kraft had provided assurances it would save jobs at Somerdale, it was shut weeks after the deal was finalised, with the loss of 400 jobs. At the time, Cadbury insisted the move was on the cards prior to the Kraft deal and the plans were too far along to be changed.
"Foreign investors are vital to the success of our economy but they should not be breaking promises made to the British people," said Labour's shadow minister for business, energy and industrial strategy, Bill Esterson.
“The government has a duty to safeguard the interests of the British workforce."
The department of business, energy and industrial change refused to be drawn on the safeguarding of jobs but a spokesperson for the department reaffirmed the government's message of wanting "the UK to be an attractive place for investment and business – boosting growth and jobs".
“Our industrial strategy will ensure the UK is the best place to start, grow and invest in business,” the spokesperson said.