Well-known Jewish philanthropist family the Dangoors have given the Royal United Services Institute (RUSI) £2 million towards the refurbishment of its historic headquarters.

It is the largest-ever gift received by the independent international defence and security think-tank in its 190-year history. The funds are earmarked for the “sensitive restoration” of RUSI’s 125-year-old London headquarters at 61 Whitehall.

David Dangoor said: “I believe that the work of RUSI has become increasingly important in these challenging times and it deserves our support. Our gift should help RUSI fulfil its charitable mission by providing independent, politically unbiased analysis and information to the wider public, in the UK and overseas.”

With the donation, which has come from the Dangoors’ Exilarch’s Foundation, the organisation has now raised approximately £7 million needed for its £10 million overall target.

Sir David Lidington, RUSI’s chair, said: "I am bowled over by the generosity of the Dangoor family and the Exilarch’s Foundation. Given the impact of the pandemic, I was concerned that the fundraising campaign for our building would take a hit. But this donation from David Dangoor and his family is extraordinarily welcome and a huge vote of confidence in RUSI and in our plans for the future."

Contractors have already moved into the building, with work set to begin in April and scheduled for completion by the end of 2022.

RUSI said the goal for its purpose-built, Grade II*-listed building “is to render a structure built for a pioneering 19th century thinktank fit for that same organisation to thrive and prosper in the 21st century and beyond”.

Dr Karin von Hippel, RUSI’s director-general, said: "I regard this exceptional and historic gift as an accolade to the quality of our research, analysis and expertise, and of course, to our hardworking and talented staff. The Dangoor gift will allow RUSI to invest in its research and conference facilities, as well as our historic Library."

The building, erected on the site of the old Palace of Whitehall, is home to RUSI’s Library for Military History, a collection of 30,000 volumes and rare works. The library will be closed during renovations.

RUSI plans to restore 61 Whitehall’s heritage features in line with Historic England guidelines while providing modern upgrades including state-of-the-art media and conference rooms.

Most of the think-tank’s events and programmes have moved online as a result of the pandemic. Its staff have been temporarily working at 123 Pall Mall, where, the organisation said, it “has maintained an active research agenda and will continue to do so during the refurbishment”.