British confectionery and soft drinks giant Cadbury Schweppes is set to finalise the details of an alliance with Spanish soda water producer La Casera.

The deal is understood to involve a share swap that will leave Cadbury with a controlling stake in the Spanish firm, and full details could be announced as early as this week.

La Casera put itself up for sale last year, buffeted by a dramatic erosion of its market share. A restructuring programme helped the company back into the black with a turnover of nearly €83m, but it is believed that talks with a number of potential buyers were unproductive.

The deal with Cadbury came after La Casera chairman Jose Arozamena revealed that the company was seeking alliances in a bid to create a multinational drinks company and wrestle market share from Coca Cola and PepsiCo in Spain, France and Portugal.