The Samsung Galaxy S4 has been available for a while now, and there is also another color version available in the UK from today, the Artic Blue Galaxy S4.
The Artic Blue Samsung Galaxy S4 is available through UK mobile phone retailer Phones 4 U, it is available on contract with a range of carriers which include Orange, T-Mobile, Vodafone and EE.
It looks like the handset is only available on contract and not available as a SIM free handset, you can find out more details over at Phones 4 U.
Source Android Central