Vodafone Group Plc and India's Tata Communications were granted on Thursday three weeks more to decide whether they want to bid for British telecoms group Cable & Wireless Plc , now valued at $1.5 billion.

Vodafone, the world's biggest mobile phone carrier by revenue, and Tata Comms now have to announce by 16:00 p.m. British time on April 19 either a firm intention to make an offer after their preliminary talks with C&W Worldwide or walk away. A previous deadline was set to expire on Thursday.

C&W Worldwide said in a statement the regulator, Britain's Takeover Panel, agreed to extend the deadline at the company's request. Sources had earlier told Reuters C&W Worldwide was likely to seek an extension of the deadline as the two potential bidders wanted more time.

Tata Communications, 26-percent owned by the Indian government, thinks it did not get as much time as Vodafone to evaluate a possible bid since Vodafone got an earlier extension, while Vodafone thinks it still has not received enough information to decide on a bid, said the sources, who declined to be named as the process is not public.

Vodafone said in February it was in the early stages of looking at a bid for C&W Worldwide, which has issued a string of profit warnings since it split from Cable & Wireless Communications two years ago.

Tata Communications, part of the salt-to-software Tata Group conglomerate, said on March 1 it too was evaluating a possible cash offer, a step that could trigger a takeover battle for troubled C&W Worldwide, which has fixed telephone lines that can be used to relieve pressure on mobile networks, and provides voice, data and other services.

C&W Worldwide also has an international cable network linking more than 150 countries, a factor that could be of particular interest for Tata Communications, which also has submarine cable assets.

Standard Chartered is advising Tata Communications, and one of the sources said the Indian company had also roped in Morgan Stanley . Rothschild and Barclays Capital are advising C&W Worldwide, while UBS is the adviser to Vodafone.

(Writing and additional reporting by Devidutta Tripathy; Editing by Clarence Fernandez)