Yeah at the time that cable was first being used to deliver broadband to UK households - i.e. around 2000 - the regional UK cable companies were already 5-10 years into consolidation being swallowed up by the mega-corporates.
When ntl bought CWC in 1999 the deal was over £8 billion. In today's money that's over £18 billion:
https://www.theguardian.com/business/1999/jul/27/1
Telewest acquired the rest of Cable London in 1999 and the next year bought Eurobell. Telewest passed almost 5 million homes.
By the time ntl and Telewest merged and then bought Virgin Mobile and got the naming rights to Virgin Media some 7 years later, it was Goliath meets Goliath with basically 3.5 million TV customers, 4.5 million mobile customers, and 3 million broadband customers. The minnows had disappeared 15 years prior.
The rough parallel in today's altnet universe would be CityFibre and CommunityFibre joining hands and then merging with Virgin Media.