Recent changes to UK copyright law might not give furniture designers the protections they expect, according to intellectual property lawyer Margaret Briffa.

The changes – which extend copyright for industrial design from 25 years after an item is first marketed to 70 years from the death of the creator – were considered a win for UK designers and brands whose products were replicated.

However, based on recent guidance from the UK Intellectual Property Office, Briffa is advising those who wish to challenge copyists that there is "a real question" over whether they will be protected.

To qualify, designers will need to prove their product is "a work of artistic craftsmanship", a criteria for which there is no statutory definition. It is up to courts to decide individual cases based on past precedent.

Briffa says they may take into account factors like the intention of the maker, the level of aesthetic appeal and how ordinary members of the public regard the work.

"Consider some iconic works from the 50s and 60s that are popular again now and that were specifically intended to be utilitarian," she wrote in a company blog post.

"There has to be a real question over whether such works would benefit from this change."

This means pieces like the widely copied DSW Plastic Chair by Charles and Ray Eames – advocates for democratic, affordable design – might not be protected from copying.

The UK government has repealed section 52 of the Copyright, Designs and Patents Act 1988. This brings the country – once derided as "a Trojan Horse for the importation of copies into Europe" – into line with the rest of the EU, which has longer-lasting copyright protections.

While the future of the laws may be uncertain following June's Brexit vote, for the time being UK copyright protections for industrial design have been broadened.

Section 52 previously exempted industrially manufactured pieces from the protections afforded to artistic works. Now designers are not explicitly exempt but instead need to prove their work actually is "artistic".

With this in mind, Briffa advises designers to prepare for possible legal challenges early.

"Where there is a real prospect the design would qualify as a work of artistic craftsmanship, we would encourage designers to put together the design history, including all drawings and sketches evidencing creation of the design," she said.

"In addition, in light of the relevance of what may have been in the mind of the designer when they created the design, it would be prudent for designers and businesses to prepare such statements now for future use in the fight against copyists."

Read the edited legal advice note on intellectual property rights for designers by Margaret Briffa:

Calling all Designers: Are your iconic 3D works about to get back into full copyright?

The long-awaited repeal to Section 52 of the Copyright, Designs and Patents Act 1988 is due to take effect on 28 October 2016.

From that date 3D works that have been mass-produced, and in respect of which registered and/or unregistered design rights have expired, may benefit from full copyright protection, which is the life of the designer plus 70 years.

It is generally assumed that iconic work will certainly benefit and the change in the law will do what designers intended – that is, give them the same protection that is granted to painters, writers, textile designers and others whose designs are two-dimensional, but that is not the case.

A 2D work attracts copyright irrespective of the artist's intention or any merit. For 3D design, the work must be judged to be a work of artistic craftsmanship by the court.

The Intellectual Property Office has published guidance on the relevant criteria to determine what would be considered a work of artistic craftsmanship. It makes interesting reading.

There are very few reported legal cases on this topic and the guidance has been gleaned from things said by judges in no more than a handful of cases.

Here is what designers would need to establish their works as being of "artistic craftsmanship":

(i) The work must combine both artistic quality and craftsmanship.

(ii) Artistic means real artistic quality and must be a work of art or fine art. It is not enough that it looks attractive. Whether something is artistic must be determined in light of evidence. This could include the intention of the maker to create a work of artistic craftsmanship, the level of aesthetic appeal, and evidence of how ordinary members of the public regard the work, as well as whether the designer already has works in his name acknowledged to be artistic.

(iii) Craftsmanship presupposes special skill, knowledge or training.

(iv) One factor that may be used in determining whether a work is a work of artistic craftsmanship is assessing the extent to which its artistic expression is unconstrained by functional considerations.

From the above, it is not difficult to see that in defending claims there is much scope for debate as to whether or not an item is a work of artistic craftsmanship.

Consider some iconic works from the 50s and 60s that are popular again now and that were specifically intended to be utilitarian. There has to be a real question over whether such works would benefit from this change.

For other works where there is a real prospect the design would qualify as a work of artistic craftsmanship, we would encourage designers to put together the design history, including all drawings and sketches evidencing creation of the design.

In addition, in light of the relevance of what may have been in the mind of the designer when they created the design, it would be prudent for designers and businesses to prepare such statements now for future use in the fight against copyists.