Changes to copyright laws in the UK and EU mean that cheaper replicas of the Barcelona chair or an Eileen Gray table will no longer be available

Mid-century design classics, such as Charles Eames chairs, Eileen Gray tables and Arco lamps are set to rocket in price, following EU regulations which came into force this week that extend the copyright on furniture from 25 years to 70 years after the death of a designer. But shoppers have six months to snap up a replica bargain, as the UK has given retailers a six-month transitionary period to clear their existing stock.

Take, for example, the famous Eames walnut and leather armchair with matching ottoman. The officially licensed and copyrighted producer, Vitra, sells them for £6,814 in John Lewis. Yet copies made in Chinese factories sell over the internet and in some stores for as little as £399.

Facebook Twitter Pinterest Mies van der Rohe’s Barcelona chair.

It is these low-cost knock-offs that will now be banned. A change in law which came into force on 28 July 2016 means that retailers will no longer be able to sell cheap replicas of iconic furniture designs and shoppers will instead be forced to pay thousands for original designs – ie those made brand new under licence with the agreement of the late designers’ estates. The six-month transition period will run out at the end of January.

Companies can currently sell replica goods providing 25 years has passed from the date the designer died, but the EU ruling – speeded up by the British government – has extended that period to 70 years. Eames died in 1978, so the new protection extends the copyright of the many chairs, tables and clocks he designed until 2048. For items designed jointly with his wife, Ray, the copyright would extend for a further 10 years, as she died in 1988.

The explosion in popularity of “mid-century modern” designs means the new law will have a huge impact on many people furnishing their homes.

Take, for example, the Barcelona chair designed by Ludwig Mies van der Rohe – hailed as one of the most celebrated designs of all time. Currently replicas can be found on sites such as Swivel UK for just £455. The officially licensed version sells at the Conran Shop for more than £4,000. Van der Rohe died in 1969, so his copyright will now last until 2039.

Facebook Twitter Pinterest The Arco floor lamp, designed by Achille and Pier Giacomo Castiglioni. Photograph: adoremodern.com

Similarly, £200 replicas of the Arco floor lamp (designed by Achille and Pier Giacomo Castiglioni in 1962) and which graced the Downing Street flat occupied by David Cameron and his family, will be removed from sale, with the Flos licensed version available for £1,420 at John Lewis.

The official Arne Jacobsen Egg chair costs £4,283 on the licensed Fritz Hansen website, but can, for now, be found for £359.98 at Vertigo Interiors, and £500 elsewhere. Gray’s chrome and glass side table sells for under £100 on some websites, yet the official version costs £433.50 licensed through Aram Design.

The changes to the Copyright, Designs and Patents Act 1988 extends the copyright for a deceased designer’s work from 25 years to 70 years. Originally the new law wasn’t meant to come into force until 2020, but it was expedited when the government decided that the time period was excessive, and to bring it into line with European intellectual property law.

Facebook Twitter Pinterest Arne Jacobsen’s Egg chair. Photograph: Alamy

The changes – designed to offer protection to British designers for a longer period of time and originally the brainchild of the former business secretary Vince Cable as a boost for UK manufacturing and innovation – are backed by Habitat founder and designer Sir Terence Conran and fashion designer Stella McCartney.

David Woods, a copyright laywer with solicitors Pinsent Masons, said the changes were intended to bring copyright laws governing furniture into line with those covering literature and music, where there have been many high-profile court challenges.

But he admits there could still be difficulties proving whether an item was a complete and intentional copy of another design: “The intent of the change to the legislation is to stop ‘exact’ copies of existing industrially designed artistic works, although this means that products that are ‘inspired by’ the works may still be allowed, so long as they do not cross the line. Identifying where that line is can be an inexact science, unfortunately, and when considering what amounts to copyright infringement, the courts will consider the question of whether a whole, or a substantial part, of a work has been copied.”

With an estimated 54 factories in China making Eames furniture alone, he predicts the closure of websites producing bargain basement, mass-produced copies of furniture, “as after all, this was their business model”.