At one point in mid-2008, we reported Brits were the world’s biggest online video junkies. A year-and-a-half later, and it’s clear that addiction continues to intensify, posing big challenges for TV programmers and big potential for advertisers.

As ComScore reports in its latest tally, Britons in February watched some 5.5 billion videos, a 37 percent year-on-year rise. Interestingly, a mix of amateur and branded content from YouTube and network fare from the likes of BBC, Sky and ITV all contributed to the impressive growth figures, showing Brits will watch pretty much anything online these days.

Mike Read, SVP and Managing Director, comScore Europe, sees the potential for online advertising in the numbers saying:

“In particular, we’ve seen eyeballs move towards the online channel to watch more long-form, professional video content, such as popular broadcast network TV shows. This trend presents a significant opportunity to advertisers, as comScore research has consistently shown that online video advertising is effective at building brands.”

Drilling deeper into the numbers and you’re starting to see some familiar names as the most influential traffic-drivers. Facebook is the fastest-growing online video property, the data show, while YouTube has an overwhelming lead on all rivals. But Blinkx too shows some impressive gains, as has Sky and BBC.

Imagine the explosion in online video consumption once the rest of the island gets the kind of high-speed broadband connections enjoyed by Scandanavians and the French.