Music Distribution in the united kingdom is now provided by the remaining major record companies. Sony/Bmg Emi and Universal. There are also some sub distributors that take care of sales and manufacturing and the co-ordination of music sales and distribution.You may find more details about this at Music Distribution
Before the internet there were many independent record distributors in the UK. But sadly they have all disappeared now as the new business model will not support the old business model of record distribution.
Although the retail outlets for music CD’s have diminished in the UK. There is still a lot of demand for physical product on album sales.
All singles now are digital download only.
Amazon play and HMV are the remaining big players in physical distribution of music in the UK with iTunes being the big beast of digital downloads.
Everyone including the Beatles is now going digital with the Beatles albums going live on iTunes today and individual tracks charting in the iTunes chart.
It is much cheaper for artists and labels to release singles now as there are no manufacturing costs and the cost of digital distribution is much cheaper that physical distribution.
The cost of video production has come right down now. So overall it is cheaper to release singles in the new music market.
I believe the future looks bright for independent labels in the UK. Once labels adapt to the new music business model and take full advantage of what the internet has to offer to music labels they will once again become a force to be reckoned with in the market place.