WADING through the mud, Martin Moon’s spade glints in the watery winter sunshine.

Over his shoulder, a digger is busily devouring the land, its bucket hungrily scarring the surface for soil before dropping it into a waiting truck.

A sister machine puffs exhaust smoke as it deposits another load in the distance.

It’s early January, and the greenfield site, in Faverdale, Darlington, will be new multi-million pound home of marine engineering firm Subsea Innovation Limited.

The company needs the additional factory and office space after outgrowing its existing base.

The spade, specially engraved to mark the occasion, is handed to Darlington Borough Council leader, Councillor Bill Dixon, for the ceremonial turf-cutting.

Months later, however, the site is unrecognisable.

The earthmovers are long gone.

Where they once roamed across the open space, the large plant is continuing its birth.

The 40,000sq ft site’s inception is striking, its blue facade, reflected in numerous puddles, emphasis of the firm’s growth.

Inside the structure, work continues at a pace, dark yellow cranes are installed overhead and a testing pit awaits its first delivery.

Bosses say the headquarters, built by Darlington-based J and RM Richardson and designed by Darlington's Architects Design Group, will allow the company to secure larger contracts and deliver more jobs.

Its existing factory will be retained for equipment storage and continued product manufacturing.

Mr Moon is delighted with the progress.

Work is expected to finish in August, with the firm likely to be fully operation at the new plant in November.

The company employs 44 workers and specialises in launch and recovery systems that deploy remotely-operated vehicles for subsea work across the world.

It also designs and makes pipeline repair and subsea sealing systems used in the offshore industry, and Mr Moon says new jobs could be on the horizon too.

The factory comes just over a year after Mr Moon, Subsea Innovation’s managing director, set a target to double sales of £7.5m in three years.

It offers scope to double its workforce to more than 70 and handle bigger contracts for oil, gas and energy clients.

He said: “We are bidding for larger work and this is a large investment to help do that us.

“This move allows us to do bigger things.

“In the past, if we have had large systems, we have had to go elsewhere and assemble them.

“However, with the new factory we can keep everything under one roof, while increasing testing and tonnage.

“We also have a floodable pit, which we can use a test tank, and that will be very beneficial for us.

“We will also have more dedicated office space and more conference rooms.

“But the existing site will be retained, which will be used for some production activities and will allow us to segregate the things we do.

“It will also give us the chance to carry out research and development in a different location that’s away from the rest of the work going on.

“Some of the products that we make will also stay because we have the ovens already in place.”

Mr Moon said the factory, which is twice the size of the company’s current home, will take away previous height restrictions, allowing it to take on larger jobs.

He said: “The fact it has extra height means we can put larger cranes in.

“I always envisaged the company would double in size, and by increasing it means we can look at larger work.

“Last year, I believe we would have got a big A-frame order from a client if we had a bigger facility, so this move is a very positive one.

“We wanted to stay in the region and looked at other places, but Darlington had everything to keep us local.

“You have to be flexible and ready to move rapidly in this industry, and such an investment will allow us to do that and strengthen our future.

“It’s all about getting your customers and keeping them for life.”

Mr Moon also praised builder J and RM Richardson for its work.

He added: “They have done a very good job and have worked around the weather extremely well.”

Coun Dixon, who is also deputy chairman of Tees Valley Unlimited local enterprise partnership, said the plant represented a major boost for industry and was a coup for Darlington and the North-East.

He said Darlington was a hotbed for subsea development, citing companies such as DeepOcean, which digs underwater cable trenches, and Modus, which works with specialist underwater vehicles to survey offshore projects, who are also based in the town.

He said: “These companies are the industries of tomorrow, not just today, and this is a quality investment.

"It is not just about the site, it is skilled jobs and really signals the company's intentions.

“People can sometimes forget the importance of companies like Subsea Innovation and their impact on the local economy, but they shouldn’t.

“They are far more significant than people give them credit for.

“Who would believe that Darlington would ever be a centre of excellence for subsea work?

“We cannot even float a boat on the river, but as a town, Darlington is crucial to subsea development.

“We have worked hard with these companies to keep them here and developed relationships to make sure Darlington is always going to be the best place for their work.”