It begs the question whereupon one would wonder that if the Monopolies commission didn't exist whether the two companies would actually merge into one entity. The number of SKY channels on VM and the recent sale of the Virgin one channel to SKY could lead one to assume that.
From a TV distribution point of view, SKY has the upper hand as new customers can come on line in just about any location where they can erect a satellite dish, whereas Virgin (cable) users are restricted to the existing fibre optic network - though (in all fairness) they still have a significant number of customers.
On the other hand, Virgin wins in the capability of its fibre optic broadband service.
It is a peculiar relationship indeed, Where I would consider that the two companies (sort of) need each other - though I doubt they would actually admit that.
Si thee