The gold sovereign (valued at £1) disappeared from circulation in 1914 at the start of World War I, when it was replaced by paper money.
The Gold Rush
“It is remarkable whence all the golden sovereigns have come since they became worth 27s. 6d.* In Stamford a busy time has been experienced by jewellers and others willing to purchase them.
At the beginning of the war a call was made for patriotism. With that call a request was issued for the payment of gold coinage into the banks. No doubt many patriotic people did so enchanging it at par. but in the light of recent events it appears that not a few hoarded it in spite of the dire need of the country for the precious metal. Now there is an opportunity of selling at a profit they disgorge their savings, but I wonder if they realise what they have lost in compound interest had the money been lent to the nation, despite the fact that they are getting 7s. 6d. profit at the moment?”
Stamford Mercury, 4th March, 1932.
* about £1.37.