Administrators from the Bristol office of corporate recovery specialist Begbies Traynor have been called in to manage the closure of the business.
The 220 employees are now facing a grim Christmas - 180 have already been let go and the remaining 40 will be made redundant at the end of the month.
Joint administrator Simon Haskew said that tightening economic conditions had made it difficult for the company to renegotiate financial facilities and consequently the directors had made the difficult decision to call in Begbies Traynor.
Black Horse was established in 1985 and operated from offices in Cricklade, Wiltshire; Wellington, Somerset; and Caldicot, South Wales. At its peak the company had turnover of around £25 million.
Key assets include a substantial fleet of plant. If a single buyer is not found, this is likely to be shipped off to auction. The plant fleet includes approximately 70 Kobelco and Kato excavators, 66 dumpers and four telehandlers, as well as compressors, rollers, pumps and other items. Company policy has been to keep equipment for no more than three years.