Engineering and joinery group DMA swung back into profit after abandoning loss-making national construction work in its mechanical and air-conditioning business.

The Gillingham-based firm, which is owned by chairman Stephen Kingsman, a deputy lieutenant of Kent, saw turnover fall 34% to £23.2m in the year to the end of September.

However, it made an operating profit of £70,000 compared to a £3m loss a year earlier, its latest accounts show.

The results are the first fruit of a turnaround plan led by chief executive Andrew Wood after the group suffered losses of £4.5m between 2012 and 2015.

“In 2016, the turnaround was secured with a return to profitability and a capital restructure by the owner in order to put the balance sheet on a firm foundation for the future,” said Mr Wood.

“With the turnaround complete the future for DMA is exciting.”

The firm owns Denne Joinery, which traces its history back to 1803 and mainly fits out high-end residential property in London.

The joinery, which kitted out the One Hyde Park development in the capital, made a pre-tax profit of £195,000, down 8%, with turnover down 22% to £3.8m.

“In London we want Denne Joinery to be an automatic entrant onto tender lists of our target clients,” said Mr Wood in his company report.

“Our strategy is to therefore continue to build our reputation and relationships.”

The DMA Maintenance division, which has delivered projects to more than 1,000 building owners, recorded steady pre-tax profits of £271,000 off sales of £4.2m.

DMA Mechanical and Air Conditioning gave the group its biggest boost after three years of losses because of “long-running legacy projects with national contractors”.

It suffered a 35% drop in turnover to £16m but made a pre-tax profit of £2.9m compared to a £3.2m loss the year before.

This was after directors decided to leave the national contractor construction market because of a lack of sustainable margins. Its parent company also injected £3.4m into the business.

Mr Wood said: “This year has marked a return to profitability with a new client base of end users, consultants and local contractors.”

DMA Group’s overall pre-tax profit stood at £7,115 against a loss of more than £3.4m in 2015.

The company grew out of GH Denne, a joinery founded by George Henry Denne in Deal in 1803. It grew into a building services and construction firm but went into liquidation in 1971.

It was acquired by the Kingsman family in 1972 who rebuilt the firm and sold part of the business, Denne Construction, based in Borden, near Sittingbourne, to the Leadbitter Group in 2006.

Denne Joinery is based at Bramling, near Canterbury, where its director Nick Kingsman, brother of DMA owner Stephen, has gained fame in recent years for a venture importing and distributing Grenadian rum.