The Royal Mint is encouraging the public to become gold investors with the launch of an online bullion trading service that lets people buy and sell gold coins and store them in the Mint's vaults, guarded 24 hours a day by the Ministry of Defence.

From today, the Mint's vault service will allow anyone to trade gold and silver coins via its website. The Mint is hoping to cash in on interest in investing in gold by making it as easy as putting money in a savings account. The World Gold Council has suggested there is a potential £4bn latent demand for gold investment within the UK.

The Mint's trading website will provide constantly updated live prices for gold and silver. It said customers would be able to buy at the best possible price "quickly, and securely, 24 hours a day, 365 days a year". The Mint will also give customers a quote to buy back coins bought from its website and stored in its vaults.

Consumers can buy just one silver Britannia coin, worth about £19.50, but will have to store it themselves, as they would if they bought a 22-carat gold sovereign. Those wanting to keep their investment in the Mint's vaults will have to buy at least 25 gold sovereigns – worth about £4,700. The mint will charge 1% of the value of your gold per year for storage, plus VAT. There is no maximum purchase limit.

Shane Bissett, the Mint's director of commemorative coin and bullion, said: "We want to help expand the bullion market in the UK, particularly as coins offer a relatively affordable introduction. The Royal Mint is responsible for manufacturing all UK coinage and has long been trusted with the currencies of other countries too, supplying to more than 60 worldwide. The quality of our bullion coins is of an extremely high standard which cannot be rivalled. We have been a highly respected and trusted source of coins for kings, queens and governments for over 1,000 years, and this proud heritage is means that we are globally recognised as a reliable source for bullion coins."

Those looking to invest will want to keep a close eye on the gold price, which after a decade of incredible growth peaked at $1,883/ounce in August 2011. Since then the price has fallen by about a third, to $1,220/oz. Sales of Royal Mint gold bullion coins increased after they were awarded VAT-free status. Britannia, Sovereign and Lunar bullion coins are also Capital Gains Tax free for UK residents as they are still considered to be legal tender.