The search-engine giant Google has revealed that it is developing unmanned aerial vehicles to deliver goods.

The company’s Google X advanced research division said that its Project Wing programme is progressing well; earlier this summer, packages containing chocolate bars, dog ‘treats’ and cattle vaccines were delivered to two farmers in Queensland, Australia.

The deliveries were made by a 5ft-long single-wing drone prototype with four propellers that move into different positions for different stages of flight.

In a statement, Google X said: “Self-flying vehicles could open up entirely new approaches to moving goods, including options that are cheaper, faster, less wasteful and more environmentally sensitive than what is possible today.

“Throughout history, major shifts in how we move goods from place to place — from steam-ships to the railroads, from the postal service to delivery services like FedEx and DHL — have led to new opportunities for economic growth and generally made consumers’ lives easier.”