An Algerian security official told The New York Times that three of the surviving terrorists said they were aided by Egyptian extremists who were involved in the September 11 attack on the US consulate in eastern Libya.

The Egyptians were reportedly all killed during the special forces assault on the gas plant and Hillary Clinton, the outgoing Secretary of State, said on Wednesday that the US was still investigating the link.

"This information is coming from the Algerian government related to their questioning of certain of the terrorists that they took alive," Mrs Clinton said as she testified about the Libyan attack that killed ambassador Chris Stevens and three other Americans.

She added that there was ''no doubt'' that the Algerian terrorists had been armed with weapons obtained from Libya. The link between the two terrorist attacks was claimed as it emerged that one of the Egyptian militants killed in Algeria was a former driver for BP who provided inside knowledge.

Security sources claimed that the attackers gained inside knowledge of the plant from an unnamed former worker who resigned from BP a year ago. He was reportedly killed along with 28 other hostage-takers.

Britain's Foreign Office on Wednesday identified Sebastian John, a 26-year-old civil engineer and the father of a seven-month-old baby, as the fifth Briton to be killed at the Algerian desert plant. At least 38 hostages are thought to have been killed, including Mr John, who started working for the company last year and arrived in Algeria a week earlier on a training course.

His wife, Nicola, said: ''Sebastian was the most amazing person. He was a fantastic husband, father, son and brother. There won't be a moment that goes by where we won't think of him.''

Further information about the militants came as the London Telegraph uncovered a video of them training in the desert about a year before their attack. The attackers were led by Mohamed Lamine Boucheneb, who was killed by Algerian helicopter gunships on the second day of the raid.

The nine-minute video, apparently posted on the internet by Boucheneb, features his ''katiba'', or fighting unit, called the Movement of Sons of the Sahara for Islamic Justice.

Telegraph, London