The British monarch was joined by her husband the Duke of Edinburgh, who joked about the insurance policies on the royal collection held there.
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Made up of paintings, ceramics, furniture and silverware, the collection has been amassed over centuries.
Works by artists as contemporary as Tracey Emin sit alongside older work by painters such as Rembrandt.
After speaking to the Duke, Paul Lawrence, chief underwriting officer with the global specialist insurance group Hiscox, told the Daily Mail: "I mentioned Hiscox insuring the Royal Collection and he asked if damage by mice was covered, and I said for him I'm sure everything is covered."
Later the Queen and the Duke met Watermen and Lightermen of the River Thames during a reception at Waterman's Hall in the City of London.
The Queen at Lloyds of London
The Royal Watermen are currently celebrating their 800th anniversary.
Both the Queen and the Duke looked in high spirits as they posed for pictures and met the British public.
Their visit comes a week after it was announced that Prince Philip will celebrate his 93rd birthday with the largest ever pageant of military music and precision drill.
The Duke sits as the Captain General of the Royal Marines and, performed every two years, the world-renowned Royal Marine Beating Retreat has been running for five centuries.
The Queen greets Watermen of the River Thames
This year however will also celebrate 350 years of the Royal Marines, making this an extraordinary commemoration.
Prince Philip and the Queen have been passing on more duties to Prince Charles and younger members of the Royal Family for some weeks now.
Reports have surfaced that the Queen, who turns 88 in April, and Prince Philip are on a "gradual downward trajectory" in the number of royal engagements they will carry out, according to The Telegraph, as the Queen’s appearance at celebrations for the 70th anniversary of the D-Day landings in June will be her final engagement overseas.
"We have been told this will probably be the Queen's last official foreign visit," a French government official told the Daily Express.