Another bump in the road: Toyota faces recall of its ultimate 'green machine'

Japanese giant may have to add 370,000 Prius cars to growing list of faulty models

Toyota is preparing to recall 270,000 Prius models in the latest of a series of embarrassing gaffes that threaten to wreck a reputation for reliability that has taken decades to earn.

The company confirmed for the first time that British owners have complained of a loss of braking power in the Prius. Similar complaints have formed the basis of angry claims in the US, where it is suspected of having contributed to four crashes.

The problem relates to the software controlling the brakes of the world's best-selling petrol-electric hybrid vehicle. Owners say there is a short lag between their applying the brakes and the brakes taking effect when they are driving on bumpy roads.

Japanese press and TV reports suggest that Toyota has decided on a worldwide recall of the latest Prius models and a leaked email from Toyota in the US indicated it would take place in the next few days. Toyota UK said there was "no official announcement" on a recall, and insisted the problem did not relate to safety but was about a "sensation" felt by owners. About 5,000 models of the third-generation Prius sold in the UK between last August and January are affected. Software on showroom models of the car, which costs £20,000, has been corrected.

The controversy follows the recall since October of more than 8 million cars worldwide because of two separate problems with acceleration. Recalls have affected 3.8 million cars because of the risk of the driver's rubber mat interfering with the accelerator pedal. A further 4.2 million cars were affected because of the risk of a jammed pedal sending the vehicle out of control. Toyota UK says it became aware of the latter problem in November, which prompted it to announce a recall at the end of January.

This week owners should start receiving letters offering free repairs during the next two months. Toyota advises motorists whose accelerator is stiff or juddery to contact it immediately since cars with signs of problems will be repaired first, followed by older models. According to Japan's largest newspaper, the Yomiuri, Toyota decided on Saturday to recall the Prius in Japan and would announce the move early this week after consulting with the Japanese Government. Japan's Kyodo News agency and TV Asahi carried similar reports.

Bob Carter, a Toyota group vice-president, sent US dealers an email on Friday night saying that the carmaker was working on a Prius repair plan and would disclose details this week. At least 100 drivers of Prius cars in the US have complained to the Government that brakes seemed to fail momentarily on uneven surfaces. The US Government says the problem is suspected in four crashes involving two minor injuries.

In the email – reported by the Associated Press news agency – Mr Carter said public awareness of the problem had prompted "considerable customer concern, speculation, and media attention due to the significance of the Prius image." He added: "We want to assure our dealers that we are moving rapidly to provide a solution."

The company intends to run 60-second TV ads in the US this week to remind customers of its 50-plus years "of building safe, reliable vehicles". In a further sign of its concern at the damage the recalls have done to its image, it placed full-page adverts in the British press last week reassuring customers of its determination to act swiftly.

In the UK, a spokesman said: "There have been some reports about the feeling of the brakes on the Prius. There is no safety issue, there's no issue with the brakes not working. It's customers who feel they are not working."

He confirmed there had been reports of the problem in the UK, but could not say how many. On Friday night, Toyota placed a notice on its website saying that there had been no reported problems with the Prius in the UK.