British media revealed Sunday that intelligence officials have reason to believe the terrorists who planned, or even carried out, the downing of a Russian airliner in Sinai last Saturday were British nationals who joined the ranks of Islamic State.
Officials at Government Communications Headquarters intercepted "chatter" in which numerous jihadis - including those with London and Birmingham accents - are heard celebrating the crash.
One senior intelligence source said the recordings suggest there is a "definite and strong link" between the British jihadis and the suspected bombing.
“There has...been some internet traffic suggesting there was British involvement in the attack. We know there are British jihadis in Egypt fighting with members of Islamic State," the source said.
“They were trained in Syria and are now hardened terrorists. Some of them have an electronics background and have been developing sophisticated bombs.”
Intelligence experts believe Metrojet Flight 9268 was destroyed as the result of an explosion in its luggage bay shortly after the jet took off from Sharm al-Sheikh airport last weekend.
The airplane's two black box flight recorders revealed a "very sudden explosive decompression" 24 minutes into the flight.
Britain, meanwhile, suspended flights to the Egyptian-controlled airport last Wednesday over the crash, which killed all 224 people on board.