There were concerns Britain may have increased the chances of a terrorist attack on its soil today, after it offered help with France's military adventure in Mali.
Worries were heightened after Islamist forces in northern Mali vowed to avenge France's air strikes, which have prevented their forces marching south to the capital, Bamako.
"France has attacked Islam. We will strike at the heart of France," a leader of the Movement for Oneness and Jihad in West Africa (MUJAO), an offshoot of Al Qaeda in the Islamic Maghreb (AQIM), told the AFP news agency.
Asked where they would strike, he added: "Everywhere. In Bamako, in Africa and in Europe."
In the UK there were grumbles of discontent over David Cameron's decision to provide two RAF C-17 Globemaster cargo planes to French forces.
Labour MP Paul Flynn told the Daily Mail: "We are stirring up a hornet's nest and that could lead to retribution.
"These military interventions always start quietly and then after a while, when things don’t go to plan, we get sucked in and we end up in another endless and costly war."
British assistance may not be as reliable as France expected anyway. Despite assurances from the prime minister that the UK had lent them "our most advanced and capable planes", one broke down in France.
Cameron said he took the decision because France is a close ally and participating in the operation would help make Britain more secure.
"There is a very dangerous Islamist regime allied to Al-Qaida in control of the north of that country," he told the Today programme.
"It was threatening the south of that country and we should support the action that the French have taken.
"We were first out of the blocks, as it were, to say to the French 'we will help you, we will work with you, we will share all the intelligence we have with you and try to help with what you are doing'."
France has also asked the US for help with drone supplies, which it is expected to agree to.
The UN security council meets tomorrow to discuss the fighting in the former French colony.