Toothy, open mouthed grins are being outlawed from passport photographs of people traveling to Britain in a bid to fight terrorism, the UK Passport Service (UKPS) said Friday.

Long fringes, sunglasses and head coverings, along with dummiesin babies' mouths, are also banned under the new regulations introduced recently to comply with strict new US standards.

"Photographs must show no shadows, your face looking straight at the camera, a neutral expression, with your mouth closed," the new rules said.

Reports here said the scanners used at airports work by marching key points on the holder's face, such as the mouth and eyes, with the photograph. It is easier for the scanners to recognize a neutral expression with the mouth closed.

"These new guidelines are an important step in the development of the new biometric e-passport and use of facial recognition technology that will be introduced in 2005 as part of the ongoing fight against fraud and international terrorism," UKPS Chief Executive Bernard Herdan said in a statement.

"When the mouth is open it can make it difficult for facial recognition technology to work effectively," said a Home Office spokesman.

The UKPS is planning to implement a facial recognition image biometric in the British passport book from late 2005 to early 2006.

Source: Xinhua