City car triplet the Toyota Aygo, Citroen C1 and the Peugeot 107 have been demoted to three stars in the latest Euro NCAP safety tests.
All three cars tested were the recently-introduced facelifted models, but they were all marked three stars from the safety body – down from four when they were first tested in 2005.
NCAP said the cars "have failed to keep abreast of latest safety developments and standards".
Dr Michiel van Ratingen, Euro NCAP secretary general, said: "Our test protocols have evolved significantly over the past few years. There are more tests and the requirements have become more stringent.
"Despite this, many manufacturers have engineered their latest cars to achieve the highest score. On the other hand, we see that some manufacturers continue to offer popular best sellers without making the necessary incremental updates to safety. It is those models that obviously fall behind other, more modern cars competing in the same category."
The current model Aygo and its twins lack basic items such as side impact airbags and electronic stability control as standard equipment.
In response to Euro NCAP's tests, Toyota has made a commitment to make side thorax airbag; side head curtain airbag; electronic stability control; passenger seatbelt reminder; and ISOFIX and top-tether in rear outboard seats as standard equipment by July 2013 in all European countries.
Citroen and Peugeot have also committed to do the same.
Euro NCAP rated the cars with this equipment onboard, but warned without these safety features fitted, the results would "have been much worse".
Dr van Ratingen added: "Consumers should buy cars on the basis that the more recent the star rating, the safer the car."
The three cars' main rivals all have better crash test results: VW Up/Seat Mii/Skoda Citigo hold a five-star rating while the Hyundai i10 and Kia Picanto have four stars.