Russian plane in Sinai: Philip Hammond says there is a 'significant possibility' Isis responsible for crash

US officials have also said it is 'most likely' that an Isis bomb is responsible for the plane's crash

The wreckage of the A321 Russian airliner in Wadi al-Zolomat, a mountainous area of Egypt's Sinai Peninsula (AFP/Getty Images)

Britain's Foreign Secretary has said there is a "significant possibility" Isis is responsible for crashing the Russian passenger aircraft in Egypt.

The airbus A321 came down on Saturday, shortly after taking off from Egyptian resort Sharm el-Sheikh en route to St Petersburg, killing all 217 passengers and seven crew on board. Investigators have scrambled to attempt to uncover the cause of the crash.

“Isil Sinai have claimed responsibility for taking down the Russian aircraft, they did that straightaway after the crash,” Philip Hammond told Sky News.

We have...concluded there is a significant possibility.

&#13; <p>Philip Hammond</p>&#13;

“We have looked at the whole information picture, including that claim but of course lots of other bits of information as well and concluded that there is a significant possibility. I can’t put it stronger than that.”

The terror organisation, also known as the Islamic State, claimed responsibility in the hours immediately following the crash.

On Wednesday, the group’s affiliated branch in the Sinai Peninsula also released an audio tape claiming they had brought down the crashed Metrojet. “We downed it, so die in your rage,” the recording alleged.

The message also challenged Egyptian authorities to “prove” the cause of the crash was not Isis.

Egyptian officials have rejected the group’s claims, with president Abdel al- describing such statements as “propaganda”.

Mr Hammond’s latest remarks are a significant escalation of his comments on Wednesday night, following a meeting with David Cameron and the government’s crisis response committee.

"We have concluded that there is a significant possibility that the crash was caused by an explosive device on board the aircraft," Mr Hammond said last night.

Meanwhile, all UK flights to and from the popular coastal resort have been delayed.

A Number 10 spokesperson said on Wednesday “more information had come to light” when asked about the decision to suspend 19 flights from Sinai on Thursday.

Downing Street is working with commercial airlines to bring approximately 20,000 Britons home, although it is hoped that flights will resume on Friday.