Romance comes in many forms. Most of them, in the modern world, involve money. It may be the initial wining and dining; or one of the more extravagant displays of affection required to put a relationship on a more permanent footing; or just one of those periodic injections of the romantic spirit that are so important for keeping such relationships going. There are the various forms of romantic entertainment books, films, music with which we put ideas into one another's heads, or to which we escape when reality doesn't quite match up to our dreams. And then there are the various correctives flowers, chocolates, holidays that we often use to put relationships back on the right track when, say, one of the partners has been working away (or, worse, playing away) for a while.
Not every romantic gesture has to be expensive, but, taken together, it all adds up to an industry that, even in the current climate, is booming.
You can see this in the continuing success of that pillar of the romance industry, Mills & Boon. A hundred years after its first book, the publisher now churns out some 2,000 books a year. You might not know anyone who admits to enjoying Mills & Boon titles, but it is equally unlikely you will find someone in the English-speaking world who hasn't heard of them. Globally, they sell 130 million books every year 10 million of them in the UK. To put that into context, Harry Potter has shifted a mere 400 million in 11 years.
The tone has evolved over the years. In the Twenties when the brand's popularity really took off female readers' romantic aspirations probably went little further than some compliments, maybe a gift or two; a date into which a lover had put some thought. Today's romantics have steamier expectations but Mills & Boon can satisfy them: your 3 will typically buy you a narrative led by a woman's yearning and a man's touch with titles such as Coming Undone ("Waves of pleasure"), The Novice Bride ("Innocent bride, conquering husband") and The Shocking Lord Standon ("Rich, vivid and passionate").
Mills & Boon's marketing director Clare Somerville says that the books reflect how romance has evolved along with society the heroine is now more likely to be a neurosurgeon than a housewife, and descriptive sex scenes are commonplace in some of the Mills & Boon sub genres; in fact, they lead the plot as long as the protagonists are romantically interested in one another. "Part of the enjoyment for our readers is they know to a certain degree that certain conventions are going to be followed," she says. "There is a framework and a premise, which is that a couple are going to meet, there are going to be quite a lot of obstacles on the way to them achieving happiness, but ultimately the ending is going to be uplifting, and leave you with a positive feeling".
Literary purists will always have reservations about the books as literature with their repetitive plots, two-dimensional characters and gender stereotyping but as a product they are hard to fault, with an annual UK turnover of around 20m. Their example, believes Somerville, has informed more inventive romantic reads. "We're definitely the precursor to modern chick lit such as Bridget Jones, but we're also the child of Jane Austen and the Brontës."
And if Somerville sounds less worried than many about the hard economic times ahead, perhaps that's not surprising: it was during the Depression of the Twenties and Thirties that the imprint really took off. "People wanted to escape the hardship of the depression and general strikes," she explains. "What women wanted, and what we could make money out of, was light fiction. They concentrated on ramping up the light fiction of the time, and the growth of the lending libraries in the Thirties was a great conduit for romantic fiction."
But it's not just publishers who can profit from the earning power of romance. The outlook also looks rosy for the British greeting card industry, whose incredible success in recent years suggests that most of us still struggle with putting our romantic thoughts into our own words. In 2006 alone, 2.87 billion cards were sold in the UK with a combined value of 1.306bn. That's 48 cards per person.
"We're huge fans of slushy cards in the UK," explains Sharon Little, general manager of the Greeting Card Association. "We wonder whether it is because people are still quite stiff upper lip when it comes to face-to-face meetings, and need some medium to convey their feelings".
No other country has quite such an embedded culture of sending and receiving cards. Little claims the UK is 10 years ahead of anywhere else in terms of design, and there are around 800 card publishers operating around the country. It is a vital industry as far as the economy goes: one in six retailers stocks cards, and hot spots include Nottinghamshire, Yorkshire and Lancashire, where cards have stepped into the shoes of heavy manufacturing as major employers.
Chocolates are another tried and tested way of saying "I love you", and, once again, despite the credit crunch sales are booming. The seasonal and boxed chocolate market is now worth 1.246bn, a significant increased from 1.180bn in 2006, when a heavy downturn in the market was predicted.
Times have moved on since the days when a lady was happy with a stealthily delivered box of Milk Tray. Posh chocs are where it's at, and the provenance of the cocoa is all important. Luxury food halls and bespoke chocolatiers such as Godiva and Green & Blacks are gaining ground and squeezing businesses such as Thorntons, long the chocolate king of the high street. The big food producers have not been slow to notice the trend towards luxury which suggests that chocolates are now being bought for special occasions, no doubt many of them romantic and three years ago Cadbury Schweppes bought Green & Blacks for 20m.
Flowers top even chocolate in terms of revenue. The UK trade in cheap bunches of tulips and costly hand-arranged bouquets is worth 2.2bn annually. On Valentine's Day, of course, most of that trade is done in red roses, a flower associated with love, passion and romance.
A more costly way to express feelings for a loved one is to buy a piece of jewellery. The market is worth around 2.5bn, an 11 per cent increase over five years, and the most successful jewellers are those offering high quality pieces in distinctive designs. "Upmarket jewellery is often bought for sentimental reasons," says Mintel's senior fashion analyst Katrin Magnussen. "This means that the market is likely to hold its own in these more challenging times." Platinum the engagement and wedding band of choice for young women is the real mover. Sales are worth 75m and have grown 36 per cent since 2003.
There are those who say that flowers and chocolates are no indication of how a person feels for another, but when it comes to romantic gestures the figures show we are fairly conformist in our tastes. That said, buying gifts as an expression of romance is so deeply engraved on our nation's psyche, it looks as if the practice might withstand even the toughest of economic shocks. St Valentine must be turning in his grave wishing he had trademarked his name.