The Duke of Westminster, the UK’s second richest person with an estimated £10bn fortune, is donating £12.5m to the fight against the coronavirus pandemic after being “humbled” by the dedication of NHS workers. The NHS Charities Together fund said it was “incredibly grateful for this most generous donation”, but some politicians and inequality campaigners pointed out that the gift equates to just 0.1% of the Duke’s centuries-old inherited wealth. Hugh Grosvenor, 29, the seventh Duke of Westminster and the world’s richest person under 30, said on Wednesday he wanted to “say a huge thank you to all our amazing NHS staff and everyone providing critical frontline services”. “We are all humbled and incredibly grateful that you are working tirelessly to keep us safe and keep the country functioning,” said Grosvenor, who is a close friend of the royal family and godfather to Prince George. “As they keep us safe, I want to help provide as much support to them and their families as we can.” Politicians and campaigners, however, suggested that perhaps Grosvenor – who paid no inheritance tax on the bulk of the family fortune after his father Gerald Grosvenor’s death in 2016, as it had been transferred to trusts – could dig a bit deeper into the family coffers. A spokesman for Grosvenor said: “The trusts, being onshore, pay income tax, capital gains tax and – via the 10 yearly charge – inheritance tax.” The spokesman also said estimates of the Grosvenor family wealth were “speculative”, and the last official valuation in December 2018 put net assets at £5bn. Clive Lewis, the Labour MP for Norwich South, said “all philanthropic endeavours are good and to be welcomed”, but added that the multimillion-pound gift “won’t even leave a dent” in Grosvenor’s fortune. “There is an acute awareness at this time of crisis that there are a record number of billionaires in the world, and their wealth has been rapidly increasing,” Lewis told the Guardian. “My message is to thank them for any gift but also to tell them that there will be many people – myself included – who will be asking: ‘Is it right that people who are putting their lives on the line to fight this virus are some of the lowest paid in our society?’ And at the other end, there are people who can give away [millions] and it won’t even leave a dent in their fortunes.” Lewis said gifts from Grosvenor and other members of the global super-rich have “come from a good place but they have thrown into stark contrast the gross inequalities in society”. The Facebook founder, Mark Zuckerberg, has committed $30m to Covid-19 research from his $67bn fortune, while China’s richest man, Jack Ma, has pledged $14m to support vaccine research from his $44bn wealth. The Duke, whose Grosvenor Estates company owns hundreds of acres of prime real estate in Mayfair and Belgravia in central London, said he was donating £5m to NHS Charities Together to create a ‘family fund’ that would support NHS workers and their families. A further £3m will go towards national medical research and development linked to Covid-19, and £2m will be given to charities and organisations helping support people suffering from the economic and societal impact of the pandemic. The £10m donation announced on Wednesday comes on top of £2.5m given in March to charities helping vulnerable families struggling to feed children who would normally receive free school meals. Wanda Wyporska, the executive director of the Equality Trust, said: “While any donation to the NHS at this time is to be welcomed, the billionaire duke could have made a transformative donation rather than scrabbling about down the back of a few of his sofas for some loose change.” Luke Hildyard, the executive director of the High Pay Centre, a thinktank on excessive remuneration, said: “This is undoubtedly a well-intended gesture, so it feels churlish to note that it represents a pittance of the Duke’s total inherited wealth or the annual rents he collects from his vast array of inherited property.” Grosvenor is the UK’s second-richest person, after the Ineos chemicals magnate Sir Jim Ratcliffe with £12bn. A spokesman for Ratcliffe, who aims to produce 4m bottles of hand sanitiser a month free for the NHS and hospitals in Europe, said the billionaire had also made a “substantial” personal donation to the fight against Covid-19. The duke inherited the family fortune despite being the third of four siblings, as he was the only son. His 21st birthday party at Eaton Hall, the ancestral seat in Cheshire, reportedly cost £5m. He hosted about 800 guests, including Prince Harry, at the “black tie and neon” bash, where comedian Michael McIntyre and hip-hop duo Rizzle Kicks topped the bill. Speaking about his son in 1993, Gerald Grosvenor said: “He’s been born with the longest silver spoon anyone can have, but he can’t go through life sucking on it. He has to put back what he has been given.” • Coronavirus and volunteering: how can I help in the UK?