When there's a coronation, a royal wedding or the birth of a royal baby, there is always a boom in the sale of royal souvenirs and keepsakes.

While some may be more conventional – we're thinking of tea towels, jewellery and mugs – others are slightly more unusual...

The weirdest royal memorabilia sold to collectors

Royal dog collars

Although our Queen plumps for corgis as her canine of choice, the pug has long been the favoured pooch of royalty. The Duke and Duchess of Windsor had as many as 11 of these feisty hounds – apparently, they all ate out of silver bowls and were perfumed with Miss Dior!

I was particularly taken by a group of five dog collars and a lead that were sold in 2008 by Bonhams in New York. This little collection gives us a candid insight into the personal life of the couple and the affection they held for their dogs.

One of the tags is inscribed, ‘I belong to the Duke of Windsor,’ which would make any small dog feel much more important. They sold for a very reasonable $1,680 against a $600-$800 estimate.

If you too are a dog lover, take a look at our guide to buying antique dog figurines.

Queen Victoria's wedding cake

I once tried explaining to a Frenchman that the British give all their wedding guests a piece of the cake and that it was also customary to never eat it. He thought I was mad.

It’s a tradition that has strong historical roots and high on my list of unusual royal memorabilia is a box stuffed full of royal fruit cake that arrived at the Roadshow in Swindon last year.

Every piece (and there were well over a dozen) was individually wrapped and annotated with details of the christening, wedding or birthday from which it had come – all related to Queen Victoria, Albert and their family.

The box also contained all sorts of wonderful items, including part of Victoria’s wedding dress train. Assembled by a person in service and passed on through the generations, the collection was certainly unique and I had no hesitation in valuing the box and its contents at £5,000.

Coronation chairs

It’s hard to imagine how some of the more unusual pieces of royal memorabilia come on to the market. An invitation to the coronation or a place card are well within the realms of possibility… but the furniture?

It seems that those who occupied the chairs and stools from past coronations were given the option of purchasing them; the remainder were auctioned off by the Ministry of Works. If you fancy the idea of parking your posterior in the same position as a blue-blooded bottom, then these wonderfully undervalued ‘privileged perches’ can be bought at auction remarkably cheaply.

More like this

Between £50-£100 will secure quite a good little velvet upholstered Maple & Co George VI coronation stool. However, there are some exceptions to the rule and the recent, well-publicised Althorp Attic Sale saw a group of two chairs and a stool used in the coronations of George VI and Elizabeth II realise £6,875.

Fan of royal furniture? Find out more about the iconic Prince of Wales Investiture Chair.

Champagne from Charles and Diana's Royal Wedding

At most of the weddings I’ve been to, champagne is not something that’s often left over. Which is why I find it slightly mysterious when rare champagne from Charles and Diana’s wedding breakfast comes on to the market.

The Cuvée Dom Pérignon 1961, the year of Diana’s birth and specially bottled for the couple, was apparently shipped to the tune of 90 bottles (all drunk) and 12 magnums, two of which Dominic Winter Auctions have sold since 2004.

A toast with this historic tipple would have cost you a tidy £1,250 in 2007 but will no doubt be a good investment given its rarity. A bottle (never mind a magnum) of this vintage without royal connections would currently cost about £700-£1,000 from a specialist vintner.

Fancy a tipple? Check out our round-up of the best champagne and sparkling wines on the market this year.

Queen Victoria’s underwear

Proof that Queen Victoria’s smalls were not so small was had when a pair of her bloomers with an, ahem, ‘stately’ 50-inch waist sold for almost £5,000 at Hansons Auctioneers in Derbyshire in 2008. The subject of royal underwear is a delicate one but the market is booming and, for many collectors, articles of Victoria’s more personal apparel are the ‘crown jewels’.

Such items usually fetch hundreds of pounds. In March last year, for example, Lyon & Turnbull sold a pair of Victoria’s black-and-white hand-stitched stockings – believed to have been her favourite design in the 1870s – for £550.

On some occasions though, the prices go sky high. Shortly after the sale of Victoria’s bloomers, a similar pair of stockings, also at Hansons, ran up to an amazing £8,000. They are now on display at Ruddington Framework Knitters’ Museum in Nottingham.

You might also be interested in the instruments Queen Victoria played and owned.

Find out more about royal memorabilia and how to start your collection. Even if you don't have a pair of Queen Victoria's pants, there might be something more appealing...