Kalyx was the new name for UK Detention Services (UKDS). Sodexho, which fully owned UKDS at the time, renamed the company as Kalyx in October 2006. Kalyx continued to run Harmondsworth IRC until 2009.
Sodexho said: “Kalyx is derived from the botanical term calyx, which is the whorl of leaves, or sepals, forming the protective covering of a flower bud. It is a symbolic representation of protection and care and it can also be associated with growth of the individual and strength – all attributes for which we are known and respected.” 
In December 2006 Kalyx was fined over £5 million by the government for unspecified 'performance failures'. Kalyx also operated HMP Forest Bank at Salford, HMP Bronzefield at Ashford, Middlesex and HMP Peterborough
- Prison Privatisation in Scotland, Scottish Consortium on Crime and Criminal Justice, December 2006, p4
- FM-World, 'Sodexo rebrands its prison services globally', 29 October 2010