Britain is to airlift hundreds of chemical weapons detection and protection kits to Syrian rebels as part of its first shipment of non-lethal equipment since a European Union arms embargo was relaxed to allow battlefield supplies.
The shipment was being assembled as US politicians heaped pressure on President Barack Obama to intervene in the Syrian civil war following a poison gas attack that killed at least 25 on Tuesday.
British Prime Minister David Cameron told the House of Commons a feeble international reaction was allowing Syria to fall into a Bosnia-style spiral of death.
Syria's regime and its opponents have traded accusations of using chemical weapons in the town of Khan al-Assad, near Aleppo. Bashar al-Jafaari, Syria's ambassador to the United Nations, demanded a "specialised, independent and neutral mission" to investigate the incident. The rebel Syrian National Coalition has also demanded an international inquiry.
Alongside body armour and armoured vehicles, the suits will be part of the first shipment of British equipment sent within weeks via Turkey to the front line.
"Protective equipment in the MoD [Ministry of Defence] stores is very effective for activists engaged against the regime on the ground and if it is known that kits are deployed we judge it less likely that the regime would use it," said an official involved in the planning. "But if there are chemicals used it will allow the rebels to detect it accurately and the world to react."
Mr Cameron said the chemical weapons threat was one reason to remove the embargo on the rebels altogether. "I felt sitting round the European Council chamber there was a slight similarity between some of the arguments that were being made about not putting more weapons into Syria that seemed to me to be very familiar to the discussions we had about Bosnia and the appalling events that followed," he said.
Robert Ford, the US ambassador to Syria, said America so far had "no evidence to substantiate" claims that chemical weapons had been used and Mr Obama's "red line" crossed.
However, the administration shared widespread concerns that the pink-white smoke and chlorine smell reported by victims was a chemical material.
The alleged use of chemical weapons prompted senators from both parties in Washington to press Mr Obama to intervene. Carl Levin, the Democratic chairman of the Senate armed services committee, called for strikes on President Bashar al-Assad's military facilities and for a no-fly zone to be imposed.
Two Republicans, John McCain and Lindsey Graham, reiterated their long-standing demand for the US to step in, with Mr Graham even suggesting the US put "boots on the ground".
In an effort to show his regime's resilience, Mr Assad appeared in public yesterday at a Damascus fine arts centre.
If there are chemicals used it will allow the rebels to detect it accurately and the world to react.
King Abdullah II of Jordan warned that Mr Assad's regime was doomed and that an Islamic fundamentalist state was likely to emerge. "The most worrying factors are the issues of chemical weapons, the steady flow or sudden surge in refugees and a jihadist state emerging out of the conflict," the king said.
An estimated 500,000 Syrian refugees have crossed into Jordan in the past year.