What’s the strangest thing you have ever seen at auction? I was asked the other day. A good question, but difficult to answer after several decades in the job.

Thinking back, though, several items stand out – not necessarily ones that passed through my hands, but nevertheless memorable.

The New Patent Exploding Trench was one. A Great War toy produced briefly by Britains, it involved a wooden and fabric trench loaded with six lead riflemen of the Gloucestershire Regiment. When hit, a specially placed flagstaff set off a cap, which made a loud report, shaking the trench and “killing” the soldiers. Why a British factory should have put British soldiers rather than the enemy in the trench is anyone’s guess, but it was a marketing disaster, and the toy was soon withdrawn. The result? A rare collectable that has made a decent four-figure sum in the two or three times it has appeared at auction over the past 20 years.

Perhaps the most chilling thing I have seen was not at auction but at a restoration firm. What looked like a framed piece of parchment turned out to be a collection of tattoos cut from the bodies of French soldiers in the field of Waterloo. Now who would want to buy that?

Almost as chilling – and certainly intriguing – is the Fiji Mermaid. This has its origins among Japanese fishermen, who sewed parts of different animals together to create chimera – in this case the head and arms of a monkey sewn to the body and tail of a fish.

They first came to Western notice after the captain of an American ship, thinking it a real creature, bought one from Japanese sailors in the early 19th century for thousands of dollars. The great American showman PT Barnum displayed it as a curiosity in the 1840s.

As a trip to Wikipedia will attest, Barnum understood how to generate publicity, writing to the newspapers under various pseudonyms on the subject of the Fiji Mermaid and creating a ruse whereby his associate booked into a Philadelphia hotel, secretly showing the creature to the manager, who then insisted on spreading the word and staging a display to a select audience, including journalists.

Probably destroyed in a fire around 20 years later, by then the legend had caught on and many copies were made. Look it up on Google images and see one for yourself.

Each example is usually named after the town in whose museum it now rests.

As Easter approaches, it reminds me of one of my favourite dreams: being asked to go through the boxes of a client’s attic to see if anything emerges that might be worth selling and coming across a Fabergé egg.

These jewels are among the most famous luxury items ever produced.

The first of several dozen of these jewel-encrusted eggs (around 70 are thought to have been made of which 61 are known to have survived) was commissioned as an Easter gift for the Tsarina Alexandra Feodorovna by her husband, Tsar Alexander III, in 1885.

The House of Fabergé was established in St Peterburg in 1842, the celebrated eggs being the invention of Peter Carl Fabergé. The first, known as the Hen Egg, is an enamel shell surrounded by a gold band that opens to reveal a golden yolk. That opens too and is found to conceal a golden hen perched on golden straw. Rather like the Russian Babushka dolls, the hen itself then opens to reveal a miniature replica of a diamond Imperial crown and a ruby pendant.

Unfortunately, the crown and ruby pendant have since been lost, but the egg must have created quite a stir when first presented. We know this because such was the Tsarina’s delight that within weeks Fabergé had been awarded a royal warrant.

To make the following orders even more of a surprise, it is thought that Fabergé gave no clue even to the Tsar as to what the eggs would look like. Fabergé himself would oversee the design before handing the creation of the eggs over to a team of craftsmen, whose names have passed down through history as a result.

When Alexander’s son Nicholas II ascended the throne, he continued the tradition of presenting eggs as Easter gifts, both to his own wife, Alexandra Feodorovna, and his mother, the Dowager Empress. In all, they received fifty eggs between them, inspiring further commissions for Fabergé eggs from the Rothschild family and the Duchess of Marlborough, among others.

The Russian Revolution of 1917 put an end to the St Petersburg workshop, with the Fabergé family leaving Russia. More than a century on, the eggs sit at the centre of an impressive output of stunning silver, gold and jewelled pieces that continue to change hands at auction for stupendous sums.

I’ll keep my fingers crossed next time I’m asked to rummage through a few old boxes.

Easter Monday falls on April 21 this year. It also happens to be the birthday of our late Queen. Elizabeth II, a reminder, if one was needed, of the rich Royal heritage we enjoy. If there’s one thing we Brits do better than anyone else it is fostering our great Royal tradition, not just with pageantry and our recognition of the symbolic importance of the monarchy, but also in producing all the colourful memorabilia that goes with it.

I still own my 1977 Silver Jubilee mug, a rather tasteful design compared with some others that have emerged down the years, and a healthy market remains for all sorts of rarities, from the Victorian era and beyond – although they go back much further.

When Her Majesty turned 90 in 2016, The Royal Mint unveiled another birthday coin to mark the occasion, while mugs, plates, tea towels and any number of other collectables are already on sale. Various commemorative mugs are already on offer, ranging in price from around £8 to £25.

King Charles III’s Coronation produced another flurry of activity, and in this era of digital payments it was, if anything, even more exciting to see the newly unveiled coins and banknotes featuring His Majesty’s bust.

When it comes to Royal memorabilia – particularly coins and notes – mass production has dampened price rises over the years unless you manage to get your hands on something that has a printing or other error, making it a rarity. The real money is in items with a very personal connection to a royal personage, such as a lock of hair in a locket. Highly personalised Princess Diana memorabilia remains among the most sought after almost 30 years after her tragic death. Who can forget the eye-watering prices raised for her frocks – especially the one in which she danced with John Travolta at the White House (£264,000).

Of particular interest are hand-written letters, especially from the late Princess and particularly if they are linked to historic occasions or shed light on behind-the-scenes lives of the royals.

Even wedding cake makes the grade; £30,000 was paid for a slice of Edward VIII’s wedding cake in 1998, 62 years after the event. Of course his was the marriage that cost him the throne, so it would have been of even more historic importance than perhaps any other.