AT THE time the young sapper probably had misgivings about the trade he had just agreed with his comrade in the trenches. For chocolate was a rare luxury in the Great War and swapping a whole bar for a set of cards given away free with the cigarette ration might seem foolhardy.

Looking back now, it was the deal of the century. For while chocolate lasts a lifetime on the hips, the cigarette cards have proved an investment beyond the grave.

Produced by the company, Taddy, the 20-card set featured clowns and circus artistes and is now one of the most highly sought-after sets in existence. Bequeathed to the old soldier's son, it is now worth £15,000.

The tale was recounted by Martin Murray, a tobacconist's son from London, who in 1967 established the firm that has become world leaders in cigarette and trade cards.

Today, Mr Murray's company employs eight people full-time and has millions of cards in stock at its Hendon base, which attracts thousands of visitors every year.

Their annual publication, Catalogue of Cigarette and other Trade Cards, is more commonly known as Murray's and lists in easily understood style thousands of sets of cards identifying the maker, year of production and shop value. It also lists cards given away with confectionery, tea, comics and other consumables.

The fact that 10,000 copies of the book are sold each year highlights the level of interest, with many of the sales put down to people stumbling across a box of cards while cleaning out the loft or sorting the affairs of a deceased relative.

Of course, the prices quoted are what you would pay in the shop and the more common sets would probably not raise half that figure at auction. However, early or sought-after sets can far exceed expectation.

On confessing an interest in such cards, I was subjected to various insults by friends and family, of which "geek" and "anorak" are two printable examples.

But the fact is that cigarette cards are now being seriously considered alongside stamps, postcards and ephemera as solid investments rather than simply hobby material.

Cigarette cards originated in the States in the 1880s, the British cigarette manufacturers followed suit ten years later with India and the rest of the Commonwealth, China, and Africa also spawning sets.

The range of subjects featured is immense. There are the obvious, such as stage, screen or sporting celebrities, royalty, transport, wildlife, landmarks or national characteristics, such as flags, dress or rulers.

Then there is the more unusual, such as "poultry breeding', "life in the tree tops" and "tricks and puzzles''.

The wealth of information crammed on to each card helps explain how our grandparents had such a depth of general knowledge. Sadly, the legacy of the cigarettes themselves was not so welcome healthwise.

The Nineties saw a surge in the value of the cards and Mr Murray urges caution before clear-outs.

"There are many sets from the large companies of the Twenties and Thirties, such as Wills, Player or Ogdens, which are fascinating but very common and worth only a few pounds.

"But other sets from the smaller manufacturers are commanding large fees and have continued to prove attractive investments," said Mr Murray.

As with all investments, condition is crucial. Cards should be kept in dry conditions and should be clean and uncreased. They should never be stuck in albums.

"Collectors like the feel of cards, they want them as they were when they came out of the packet and the albums the same," said Mr Murray.

For example, a 1953 loose set of British Birds given away with Brooke Bond tea would cost £60 today and the empty album £150. The set stuck in the album would be valued at £40 in total.

Mr Murray hosts a trade fair and auction each month at the Royal National Hotel in Bloomsbury. Entry is free and it is close to King's Cross station, so perfect for those travelling to London by GNER.

The timing of the auctions - 10am to 4pm on the third Sunday every month - is ideal for those enjoying a weekend break.

The atmosphere is relaxed, with dealers happy to answer questions.

December's auction attracted interest from as far away as New Zealand and the States and illustrated how it is not necessarily the age of the cards that determines their value.

A set of 50 football club managers, issued by the Clevedon confectionery company in 1959, went for £1,400 - three times the estimate. Rare cards - often ones bearing an advertisement for a particular product - can change hands for four-figure sums and Mr Murray recently sold two for 8,000.

But they don't have to be that old to be valuable.

I remember well the football cards of the Seventies given away with bubble gum. How school playtimes would involve swap sessions or illicit gambling - skimming the cards towards a wall with the nearest taking all. Now such cards can fetch more than £100 a set, though these are in pristine condition, not scuff marked from the playground!

"Certain events can spark a surge in interest and therefore prices," said Mr Murray. "The launch of the Queen Mary has led to demand for sets which include the original liner and England's World Cup success could increase demand for rugby themes."

With up to 30 dealers attending each monthly fair, the Murray auctions are perhaps the best place to sell collections. Commission is charged at 20pc for the first £100 of each lot and 10pc thereafter and there is no buyer's premium.

Closer to home, there are specialist auctions at Tennants in Leyburn each quarter featuring cards, postcards, stamps and other collectables.

The last one saw some good prices recorded for cigarette cards, with one shoebox full of loose cards going for £700 - twice the anticipated value.

However, Tennants' expert Jane Wiltshire suggests postcards as a better investment.

"Considering the age and scarcity of some cigarette cards, I feel they should be going for more. However, prices have rocketed for postcards," she said.

"The beauty of postcards is that they appeal to different streams of collectors. A train buff will be interested in a postcard with a train on the front, a collector of stamps or postal franks will also be interested."

Ms Wiltshire says there seems to be particular interest in disasters. A postcard of the 1906 San Francisco earthquake will go for £20 upwards, while one of the Stokesley floods of the Thirties or a North-East pit disaster could go for £40.

"Certain artists are also very popular. The cat illustrator Louis Wain produced a number of postcards at the turn of the twentieth century and they can now command between £20 and £50 each," she said.

Originally ephemera meant something transitory or short-lived. Now it describes a class of collectable items ranging from boxes and labels to autographs and posters, which are lasting far longer than expected. Tennants recently saw a fairly standard 1961 letter of thanks to a contributor, signed by President Kennedy, going for £460 and six editions of the Daily Mirror of 1912 relating to the sinking of the Titanic went for £60. The rise in value of such items is put down to the power of the internet and strength of the grey pound. A computer and a phone brings any auction to your front room and there is a swathe of 50-pluses who have taken early retirement and have disposable income to indulge their passions.

"As a hobby, it keeps the mind active and disability is no bar to collecting. The rarer items, and stamps in particular, are now seen as a better investment than stocks and shares," said Ms Wiltshire.

The best advice is to spend a little time researching the "junk" you find in the loft before disposing of it.

If you become interested in collecting, a little knowledge from the likes of Murray's or the Miller's collectables books can prove invaluable when sifting through car boot sales.

Tennants offers free valuations and is preparing its catalogue for a sale of postcards, stamps, trade cards and ephemera on March 18.