The Duke of Westminster has donated an extra £10 million to the UK’s coronavirus relief effort.

The majority of the money will support the health service, through NHS Charities Together, to provide respite, rehabilitation and mental health assistance to NHS staff and their families.

Billionaire landowner Hugh Grosvenor, who is one of Prince George’s godparents, said: “On behalf of my family and everyone at the Grosvenor Estate, I want to say a huge thank you to all our amazing NHS staff and everyone providing critical frontline services.”

He added: “We are all humbled and incredibly grateful that you are working tirelessly to keep us safe and keep the country functioning.

“NHS staff and key workers don’t work in isolation. They have children and families whose health and well-being will also be highly impacted by this crisis.

“As they keep us safe, I want to help provide as much support to them and their families as we can.”

A sum of £5 million will help create a Family Fund within NHS Charities Together, while £3 million will go to national medical research and development linked to the Covid-19 illness and £2 million to charities providing frontline support to those suffering the greatest long-term economic and social impact.

It follows an initial donation of £2.5 million in March, which went mostly to charities providing essential food distribution to vulnerable families.

The duke said: “While the impact of this crisis is being felt immediately, the virus will sadly also affect people’s lives long into the future.

“That’s why I’m keen to support the longer-term scientific and socio-economic response to the epidemic.”

Ellie Orton, chief executive of NHS Charities Together, said: “We know many NHS staff have chosen to keep their families safe by staying apart and focusing their time and energy to care for their patients and save lives.

“Their dedication is not only remarkable but no doubt comes with its own price and, if I may speak on their behalf, we say a heartfelt thank you to the Westminster Foundation.”

The 29-year-old duke inherited his title, the family estate and a £8.3 billion fortune after the death of his father, Gerald Cavendish Grosvenor, the sixth Duke of Westminster, in 2016.

Close friends with the Duke and Duchess of Cambridge and the youngest of George’s godparents, Hugh is a former student of countryside management at Newcastle University, but mostly keeps out of the limelight.

He is said to “own half of London” and Vanity Fair described him as “baby-faced” and “absurdly rich”.

The Grosvenor Estate has also been offering practical support including rent-free arrangements and rent deferrals for independent and vulnerable retail tenants, charities, other commercial businesses and farms.

A disinfectant is being produced and offered freely available to local health, transport, care home and prison services, and properties in Mayfair and Belgravia have been made available to key workers and vacant properties offered to local councils to help with their relief efforts, the estate said.