Broadband provider O2 has announced plans to construct or upgrade 1,500 base-station sites to improve its 3G coverage.
A spokesperson for the internet service provider told ZDNet that it will spend hundreds of millions of pounds building "significant headroom for mobile data".
O2 aims to deliver 200 sites to London over the next 12 months, she said, adding that up to 40 could be live by this Christmas.
Derek McManus, O2's Chief Technology Officer, said that the mobile and broadband industry has seen "an unprecedented change" in consumer service requirements.
He said the introduction of world-class devices, in combination with a wide variety of data applications, has placed "an exponential demand on mobile data networks".
"We are now aggressively accelerating our network growth programme to ensure we have significant headroom for the future and retain our focus on being number one for customer satisfaction," Mr McManus added.
Last week, it was reported that O2 now has now has over 500,000 subscribers to its DSL broadband services.