Not even a hint of a smile will be allowed

From now on Canadians have been instructed to adopt a "neutral expression" for their picture, which according to ministry officials "means no laughing, smiles or frowning".

The ban officially came into effect on 15 August, but the decision could not be announced nationwide because of the huge power blackout that hit Ontario province at the time.

Suzanne Meunier, a spokeswoman for the Canadian Passport Office said the government was clamping down in accordance with a series of recommendations from the International Civil Aviation Organisation designed to make it easier for security personnel to identify passport holders.

Other restrictions include:

• Hairpieces that are normally worn are permitted as long as they do not alter the person's appearance substantially

• Although turbans and head scarves worn for religious reasons are permitted, veils which cover the face are not

• Tinted prescription glasses are allowed as long as the eyes remain visible.

The crackdown on smiling in the photographs means that a grin or flash of teeth is certainly out of the question. "The mouth must be closed," Ms Meunier said.

But for those who like to show a little personality in their travel documents there is a small window of opportunity - passport applicants have been granted a smile amnesty that will run until 3 November.

"We have already received photos with a small smile that we are ready to accept," she said.

But from the November deadline only serious photos will be allowed.