The news follows Telewest's third-quarter results last week, when it revealed that subscriber numbers to its broadband internet service had reached 70,000.
According to NTL's estimates, 240,000 UK homes have access to broadband internet services, and cable provides more than 70% of it.
NTL managing director Stephen Carter said, "This country needs broadband and we are building it -- 100,000 customers in one year, we are delighted."
NTL currently offers two tiers of broadband internet access, a 512kbps service at £25.99 a month and a 128kbps service, to rival ISDN, for £14.99 a month.
Telewest, meanwhile, offers a 524kbps service at £25 a month for users of other Telewest services or £33 a month as a standalone service.
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