HECToR started it's life in 2008 as a 59-teraflop Cray XT4. Since then, the machine has gone through a number of iterations, and in its most recent upgrade to an XE6 has attained upwards of 800 teraflops. As such, it is currently represents the swiftest supercomputer in the UK.
HECToR now has to share that honor with its new blue brother though. Yesterday, the EPCC announced that, along with the Phase 3 upgrade to HECToR, it has installed an IBM Blue Gene/Q supercomputer (No word yet on any nicknames to be given to the new blue super). The new system is said to match the Cray-built HECToR machine in floppability.