What a revolutionary idea in one of the leading DTT markets: why not move some content online. It goes to show that online TV is becoming a serious alternative, even for a relatively broadcast minded organization as the BBC.
Maybe the UK should keep going at it and thus free up some serious spectrum. A new digital transition could take place: move to a next-gen digital TV standard: maybe T2+HEVC for some of the main channels (max. in 100Hz full HD) and the rest in SD or 720p HEVC online. Plan now and in about 7..10 years those old muxes can be switched off.

In all fair honesty a second questions also presents itself: why did the BBC create this channel in the first place?
update:
More views on this issue are coming in:
With tribute to BroadbandTVNews: BBC Three to cease linear broadcasts.