Olympic medals, Jubilee coins and 2p bits – it's a licence to make money

Business is booming at the Royal Mint in South Wales. Kate Youde goes behind the barbed wire to see it at work

Most people would be happy to get their hands on one Olympic medal this summer: Marie Buckley has already picked up 4,700. Indeed, she is the only person in the world who will get her hands on every London 2012 Olympic and Paralympic Games medal.

Sitting quietly at a sewing machine, stitching a purple ribbon on to a Paralympic silver gong, she is shy and unassuming. "It's lovely," says the 56-year-old, from Tonyrefail, South Wales, of her job engraving the Olympic medals, the largest and heaviest ever made. "I have always liked the Olympics but I will be thinking I had a big part in them."

We meet in a tucked-away room, accessed by swipe card, in Llantrisant, at the foothills of the South Wales valleys. After giving up my personal belongings, being let through a fair few locked doors and changing into steel-capped shoes, I am inside the barbed-wire-fenced Royal Mint to see the striking of a gold five-ounce coin marking the Queen's Diamond Jubilee. But, in what production manager Kevin Jones says is the Mint's biggest year for commemorative coins, there is also evidence of the Olympics everywhere I look.

The 43-year-old, of Quakers Yard, one of about 900 employees, leads me into a large open-plan room where all commemorative coins and medals are struck, packaged and dispatched. The Mint is making 1,952 silver five-ounce Diamond Jubilee coins, priced at £450, and 250 gold, at an eye-watering £9,500 each.

I watch a machine operator, Bartlomiej Warot, 26, of Caerphilly, blow any lingering dust from a gold blank before lowering the die (a piece of hardened steel holding the design that is used to strike coins) into place. He then hits a button and a screen shoots down before the press strikes the blank four times with 500 tons of pressure.

Trays display some of the dazzlingly shiny completed coins. Part of the painstaking process to achieve that mirror finish involves someone polishing by hand the surface of the die for five hours. I don white gloves to carefully inspect the expensive gold coin. Technically, as it carries a £10 denomination to make it legal tender, I could spend it in the nearest shop.

Just in case I – or anyone else – were tempted to pocket a coin or two, security cameras cover the area and a Ministry of Defence police officer is patrolling the floor. But the workers are blasé about handling money every day; they see coins as products. The Mint has been part of everyday life in this area since it opened in 1968, in preparation for decimalisation.

Created by Ian Rank-Broadley, whose effigy of the Queen has featured on coins in circulation since 1998, the reverse design of the five-ounce coin depicts the Queen draped in luxurious robes on a throne. The obverse features a portrait of the Queen he has created especially for all Diamond Jubilee coins.

A Royal Mint spokeswoman stresses that commemorative coins are bought for "emotional currency", and it does not sell based on investment. Which is just as well, because experts say they have little collectible value. George Champ, of the dealers Spink, tells me afterwards that the firm pays bullion rate for gold and silver commemorative coins, meaning that you would get only about £5,000 for your £9,500 five-ounce gold coin at current prices.

While the atmosphere in the building making commemorative coins is quietly industrious, we need luminous-yellow ear-plugs to enter the noisy block on the 35-acre site that houses the production of circulating coins. On first glance, it looks as if someone has won big on a slot machine: coins pour seamlessly from one piece of equipment into a trough below at alarming speed. But what I am actually witnessing is a mechanical press striking two-pence coins.

Dave Stonehouse, 45, of Beddau, team leader for circulation coins, explains that the machine pushes a blank up to strike the top, and then down to mark the bottom, before ejecting it and repeating the process with the next blank – all at a rate of 435 per minute. That, it emerges, is rather slow. A couple of presses along, a machine is churning out 852 five-pence pieces a minute.

Elsewhere, four telling machines are counting out 100,000 pennies. Forklift trucks beep their way round the Treasury's adjoining coin store, which, according to a sign, can hold £49m. On average, the Mint produces a mind-boggling 1.1 billion UK coins every year.

Back in the main room, the walls are decorated with international flags: the Welsh site is the world's leading export mint, striking coins, blanks and medals for about 60 countries each year. A mound of intriguing square copper-plated coins turns out to be the latest batch of five-cent pieces for Suriname in South America. The Polynesian island of Tuvalu and Thailand are other currency customers, while New Zealand, Jamaica, Bermuda and Australia all turn to us for medals.

As well as making medals for UK institutions such as the fire service, prison service and royal household, the Mint supplies the Ministry of Defence with about 3,000 a month. For Ms Buckley, who makes medals honouring soldiers fighting in Afghanistan, working on the Olympic prizes gives her a different sense of pride. "The soldiers are giving up so much for us," she says. "You can't compare this [the Olympics] with that, can you?"