Sir James and Lady Deirdre Dyson got building work under way at Bath’s new Neonatal Intensive Care Unit which will see the vital facility double in size.

The Malmesbury-based inventor and his wife have helped raise the £6.1m needed for the work to begin at the Royal United Hospital.

The Dyson Centre for Neonatal Care will be double the size of the current, rather cramped NICU, and provide more space and extra rooms for parents to stay on site while their children are being treated.

At the ceremonial turf-cutting last Thursday, Lady Dyson said: “It is very exciting to finally here the word ‘go’ on this project.

“We have really enjoyed raising money for such a precious project.”

She added: “This will give the unit much more space.Currently there are wires everywhere, there’s no room for nurses and parents.

“I don’t know how the staff manage – they save lives in there.

“They are amazing and totally uncomplaining.”

The Dyson’s two sons were born at RUH, one of whom, Jacob, now 38, was treated at the NICU for a few hours.

Lady Dyson said the expanded centre would mean a lot for parents.

She said: “This will make a huge difference to families.

“Parents are often stuck here for hours with hardly any lighting to read a book and nurses buzzing around.

“It can be a frightening and stressful time.”

John Cullum, chairman of the Forever Friends Appeal, and father of musician Jamie, said the new building would be one of the most sustainable NHS buildings in the country.

He said: “We’ll be making use of natural materials such as wood and maximising natural light.

“It should be much quieter and provide a more healing environment.

“The current 1960s building is very cramped and not fit for purpose.

“Having the connection with Dyson is fantastic.

“They funded research to find out if the new unit would be feasible.

“It is a name associated with cutting edge technology and I hope the new centre will be a cutting edge facility.”

James Scott, chief executive of the RUH, added: “This will be one of the greenest buildings we have.

“It will have the lowest carbon footprint and be the cheapest to run.”