This is a tricky one to work out because there are many roles which will cover different activities but here goes:
The UK Office for National Statistics (ONS) uses Standard Occupational Classification (SOC 2010) to classify working occupations, with ‘Groundsmen and greenkeepers’ having and SOC of 5114, within the Skilled trade category.
As a comparison Gardeners and landscape gardeners are 5113, and Horticultural trades are 5112.
Statistics for August 2015 indicate that there are 29,000-30,000 people employed as a groundsman or greenkeeper (this doesn’t include volunteer ground staff), effectively all were employees and not self-employed, and all men, which we know isn’t actually the case. The accuracy of the figures is influenced by how people record their occupation, and the extent of the data gathering, so these are a guide rather than definitive.
Earlier research, carried out on behalf of the Institute of Groundsmanship (IOG), in 2008, provided an estimate of 19,264, but this also included 8,556 greenkeepers.
Forecasts for the number of employed groundsmen and greenkeepers indicate that numbers will be fairly steady for the next 5-years at around 27,000 until 2012.