Joan Harvey only remembered she had packed the paperknife when her bag was checked in Paris for an ongoing flight.

The psychologist at Newcastle University said this raised serious concerns about airport security.

However, airport officials said the security emphasis has changed and cockpit doors are now reinforced against weapons like small knives.

Mrs Harvey, whose speciality is health and safety, was on her way to a conference in Poland on risk management.

'Very sharp'

She had forgotten that the paperknife was in her hand baggage when she boarded the first leg of her flight.

On arrival in Paris, her bag was checked before her flight to Gdansk, the knife was spotted and her bag transferred to the hold.

She said: "It may only be a paperknife but it's very sharp at the end.

"I rang Newcastle airport and they said regulations had changed. But why was it stopped at Charles de Gaulle Airport?"

Kevin McNicholas, security manager at Newcastle International Airport said: "Rules are different in different countries.

"Following the attacks in the US, regulations were changed to make sure knives and things weren't taken on board aircraft.

"Since then a number of new procedures have been put in place. The most important is that aircraft have been changed so you cannot get into the cockpit. Doors have been strengthened and are now locked.

"Following these revised measures the regulator says you can now take certain items on board.

"Things like knitting needles, for example, which are longer than six inches and still have a sharp end are now allowed."