The Duchess of Cornwall today attended the annual ICAP Charity Day in support of The Silver Line.
Founded in 1993, ICAP Charity Day aims to raise funds to make a significant difference to charities internationally.
For an entire day ICAP, a City broker, donates 100% of its revenue and brokers' commission to charity. Now in its 26th year, the charity day has supported more than 2,300 charities worldwide.
This year The Silver Line, of which The Duchess is Patron, is one of 17 UK charities which will receive a share of the money raised.
Her Royal Highness met brokers on the trading floor and spoke to charity representatives.
The Silver Line was founded by Dame Esther Rantzen in 2013 and provides a freephone 24-hour helpline for older people suffering from loneliness, offering information, advice and friendship.
To celebrate the charity's fifth birthday, The Duchess and Dame Esther cut a cake, made by previous Great British Bake Off finalist Andrew Smyth.
Her Royal Highness then made a phone call to 87-year-old Margaret Laverick, from Melrose, Scotland. Mrs Laverick is a regular client of The Silver Line and has struck up a friendship with Dame Esther since using the service.
"Esther tells me you're a very special person," The Duchess said to Mrs Laverick. "I wanted to ring you up and wish you a very happy Christmas."
Dame Esther said: "It's a new charity, we're only just five years old. We've already had well over two and a quarter million callers. It just proves how huge the demand is, how great the need is.
"It's absolutely wonderful to have The Duchess of Cornwall as our Royal Patron, it means so much to us and to the older people."
To date, the helpline has taken over 2.2 million calls - currently more than 1,500 every day – with 80% of callers every month phoning for the first time.
Three quarters of these calls are made overnight and on the weekend -when other services are shut. 90% of callers live alone and more than half of them speak to no one else, sometimes for days or weeks at a time.