Staff at Guy's and St Thomas' foundation trust could face redundancy following the conclusion of a four-year dispute with the Health Protection Agency.

The staff work at Guy's independent poison advice service, which was set up in 2005, in competition with the HPA's national poisons information service. Guy's set up its own service after concerns about the governance and quality of the national service - a helpline and website manned jointly by various national centres of expertise.

Guy's requested to rejoin the national service after a positive joint review of it by the trust and the HPA in 2007. However, as the HPA does not need any extra capacity, Guy's has declared its service "unsustainable". It will stop operating in July. The trust runs several other toxicology services, which are likely to continue, but did not rule out redundancies.