The trial includes a range of ready-to-print items, such as a wine cooler and a pen holder made to look like the Olympic 2012 gold postboxes. Royal Mail is also offering a bespoke printing service for customers with their own CAD files, aimed at SMEs.

The iMakr Zortrax M200 3D printer has been installed at Royal Mail's delivery office on New Cavendish Street, although iMakr said the bulk of the printing would be done elsewhere.

"Only one printer is currently installed [at New Cavendish Street]. As demand increases we will look to providing more, but the majority of the printing will be done offsite at the iMakr Store and our headquarters," said a spokesman.

"The trial will run until January and if the results are successful it will extend beyond that."

Off-site printing will be carried out on a range of devices, including the Ultimaker 2. Customers will be able to browse products in the pop-up store and online via the Royal Mail and iMakr websites (royalmail.com/3d and myminifactory.com).

Mike Newnham, chief customer officer at Royal Mail, said: "3D printing is an emerging technology that has many applications and offers an innovative way to create unique or personalised objects.

"It can be prohibitively expensive for consumers or small businesses to invest in a 3D printer, so we are launching a pilot to guage interest in 3D printing to sit alongside Royal Mail's e-commerce and delivery capability."

Romain Kidd, chief executive of iMakr Group, said: "iMakr is excited to bring to Royal Mail its expertise in 3D printing by offering customers an introduction into 3D printing through one if its central London delivery offices and a selection of objects from MyMiniFactory.com."