IIP said the standard "showed a truly cutting-edge organisation operating at the very highest levels of people management practice".
Less than 0.1 per cent of recognised organisations have achieved the standard up to July 2009.
Since first receiving the standard in 2001, Gavin Jones has used the IIP framework to guide the business, according to managing director Will Clark.
He added: "We understand that there are only approximately 78 organisations throughout the UK that have achieved gold status.
"We are proud to be in this elite group and believe it pays great testament to the calibre, dedication and attitude of our employees."