This year records have been set in auction houses across the world. From the expected winners such as paintings by world-renowned Picasso and a racing driver's 1957 BMW, to the more obscure lots including the best selling swan decoy model in history, read on to find out what items sold well when they went under the hammer...

In December 2018, a rare signed first edition of Harry Potter and the Philosopher's Stone with the unusual 'wand' mistake on page 53, where '1 wand' is listed twice in a list of Harry's school supplies, sold for a record-breaking $159,232 (£127k) in New York. This smashed the previous record of $75,460 (£60,186) paid for a Harry Potter book at a Dallas auction in 2017.

In June 2018 a two-pointed "bicorne" hat worn by Napoleon – said to have been found on the battlefield after the leader's 1815 defeat at Waterloo – sold for $317,896 (£250k). One of 19 of Napoleon's hats thought to still exist from the 120 hats he is said to have owned during his career, it created quite a stir in the auction room as the hat had only been expected to sell for $45, 275 (£35,605).

This sketch of the fictional Hundred Acre Wood by EH Shepard was based on AA Milne's Winnie the Pooh stories. The whimsical illustration brings the world of Christopher Robin and Pooh to life with its childlike misspellings such as "Nice for picnicks" and "100 Aker Wood". It was expected to sell for between $127-190,000 (£100-150k). In fact the illustration pulled in a record-breaking $546,782 (£430k), beating the $399,914 (£314,500) record which was incidentally held by another Pooh drawing.

A new record was set for the most expensive bottle of wine sold in Europe this October. A bottle of Domaine de la Romanee-Conti – a Burgundy wine from 1945 – sold for a whopping $558,000 (£436,070). This was followed by another bottle selling for a slightly less $496,000 (£387,618) minutes later. One of 600 bottles from that year, it is a particularly rare bottle. 

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A bottle of The Macallan Valerio Adami 1926 whisky (pictured right) claimed the title of the most paid for a bottle of Scotch ever when it sold for $1.1 million (£859.6k) in Edinburgh on 3 October. Twelve original bottles were produced, with another claiming $1 million (£781m) in a Hong Kong auction in May. One bottle is thought to have been destroyed in an earthquake in Japan, while another has since been opened and consumed, making this a very rare purchase.

The handwritten letter that the Noble Prize-winning scientist wrote a year before his death in 1954 was only predicted to achieve $1.5 million (£1.2m) at auction. The letter, intended for German philosopher Eric Gutkind, challenges the concept of religion and sold for a whopping $2.9 million (£2.3m). This is a world record for an Einstein letter.

The BMW 507 Roadster became the most valuable BMW ever sold when it went to auction for $4,830,958 (£3.8m) at the Bonhams Festival of Speed sale. Just one of 252 made, the car's previous owner was John Surtees CBE – the only man to ever win the world championship on both two and four wheels – who died in 2017, meaning that this car is rare not only in type, but provenance too.

This sleek Aston Martin Zagato – often known by its distinctive '2 VEV' registration number – has broken the record for most valuable British car ever sold at European auction with a price of $12,814,109 (£10,081,500). The car has been owned by the same family for 47 years, and it's not just about its looks – the Zagato has a history of international competition, racing at Le Mans and Goodwood TT.

When Sotheby's Europe put never-before-seen jewellery owned by French King Louis XVI’s Queen Marie Antoinette under the hammer in Geneva this November, it was expected to sell well. However, no one could have predicted quite how well the collection owned by Italy's royal Bourbon Parma house would perform...

The pearl – here attached to a necklace – alone broke the record for a natural pearl sold at auction, beating the $2 million (£1.56m) estimate when it sold for $36.2 million (£28.3m). The rest of the collection sold for $53.1 million (£41.5m), which broke the record for largest jewellery sale ever.

The 18.96-carat "Pink Legacy" diamond sold for $50 million (£38.5m) in Switzerland in November 2018. Achieving a record price per carat for a pink gem, the magnificent jewel was bought by New York jewellers Harry Winston.

Romanian artist Constantin Brancusi's La jeune fille sophistiquée based on the physique of Parisian personality and British expat Nancy Cunard sold for a record $71 million (£55.9m) for a Brancusi piece in March 2018.

Suprematist Composition has become something of a bestseller for Kazimir Malevich. The 1916 abstract painting has topped its own record as the Russian artist's highest selling work when it sold for $85.5 million (£67.3m) in March. This was an increase on the $60 million (£47.3m) it went for in 2008.

This November Yorkshire-born artist David Hockney's 1972 painting Portrait of an Artist (Pool with Two Figures) broke the auction record for a work by a living artist, selling for $90.3 million (£70.6m). This beat the existing record held by American artist Jeff Koons whose Balloon Dog (Orange) sold for $58.4 million (£45.4m) in 2013.

The Peggy and David Rockefeller collection set the record for the most valuable private collection this May. The auction of 1,500 objects and pieces of art sold over a three-day auction and a 10-day online sale, and generated an incredible $832.6 million (£657m). The sale broke several records including its top lot – Picasso's Fillette à la corbeille fleurie (pictured) – which sold for a staggering $115 million (£90m), despite only being estimated at $100 million (£78.6m).

Another record-breaking lot from the Peggy and David Rockefeller collection was John Haynes Williams’ whistling swan decoy which dates from about 1910. The working decoy is very rare and its creator Williams was considered a master for his practise of creating individual bird decoys so as to reflect a real flock of birds. The swan fetched $384,000 (£302k), which was the most a decoy, or a John Haynes Williams piece, has sold for in history.

Another Rockefeller item, Gilbert Stuart's portrait of George Washington – pictured here with Christie's Chairman Emeritus, Stephen Lash – sold for $11.6 million (£9.1m), making it the highest selling piece of work by the artist.

Emperor Napoleon loved his "Marly Rouge" 256-piece dessert service so much that in 1814 he insisted on taking it into exile with him, to the island of Elba. It seems like he's not the only one enamoured with the set's butterfly designed plates. It sold for $1.8 million (£1.4m), a world record for 19th-century porcelain and more than six times its estimate.

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Another record was set when a painting of a Turkish woman in a harem by French painter Matisse sold for $80.8 million (£63.7m), which was almost double the previous record of $48.8 million (£38.5m) for the artist.

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