In a worrying development, it has been confirmed that British businesses were given permission to send potentially deadly chemicals to Syria in the build-up to the brutal conflict.
The Department for Business, Innovation and Skills (BIS) granted a number of licences to specialist firms allowing them to deliver sodium fluoride to Syria before the current conflict and European Union (EU) sanctions.
The licences allowed the sale of the chemical for commercial use in cosmetics and healthcare products, and there is "no evidence that the chemicals were used in weapons programmes", a spokeswoman for BIS said.
Scientists told The Mail on Sunday that sodium fluoride can be used to make the nerve agent sarin, which scientists believe was used in the chemical attack on the outskirts of Damascus on August 21, in which the US says 1,429 people died.
"These licence applications, which predate the current conflict and EU sanctions, were rigorously assessed and determined to be for legitimate commercial use, namely cosmetics and healthcare products," the BIS spokeswoman said.
"There is no evidence that the chemicals were used in weapons programmes.
"The Government is confident that UK export controls continue to be among the most stringent in the world."
The five licences were issued in July 2004, September 2005, March 2007, February 2009 and May 2010, the year before the civil conflict erupted.
It comes after BIS admitted issuing licences for the export of sodium fluoride and potassium fluoride to the war-torn country in January last year before revoking them several months later.
The Government said no chemicals were exported before the licence was revoked in June 2012 following EU sanctions.
Last week, UK scientists at Porton Down said they found positive evidence of sarin on samples of soil and clothing reportedly retrieved from the site of the attack.
Professor Alastair Hay, a toxicology expert at Leeds University, told The Daily Mail: "The Government's approval of sodium fluoride sales to Syria during a period when it was widely suspected the regime was stockpiling dangerous substances is deeply disturbing.
"This was a serious mistake on BIS's part as while sodium fluoride has a multitude of benign uses, such as toothpaste, it remains a key ingredient in the manufacture of sarin. Quite simply, you need fluoride to make sarin."
The G20 summit last week laid bare international divisions over whether to take military action against Syria over the attack, blamed on Bashar Assad's regime.
Prime Minister David Cameron has ruled out bringing the issue back to the Commons and he has the support of the public, according to a new poll.
It found voters opposed MPs voting again on British involvement - even if the UN inspectors concluded chemical weapons were used, by 46% to 36%.
But almost a quarter (24%) accepted that the decision to stay out would encourage other dictators to use chemical weapons, the ICM poll for the Sunday Telegraph showed.
Fewer than one in five (19%) thought the UK should join US-led strikes, in the poll which questioned an online sample of 1,951 adults from September 4-6.
Tory former cabinet minister John Redwood, who abstained in the Commons vote, urged American politicians in both Houses to vote down military action.
"When we in the UK Parliament came to speak on Syria, we did not wish to turn our backs on the world," he said in an open letter published in the Sunday Telegraph.
"Those of us who made the difficult decision not to back our Prime Minister and spoke against the use of force did so because we could not see how a limited powerful strike could make the position better."
He said there was "no consistent and convincing answer" given about who would suffer and what strikes would achieve - warning of the risks of civilians being used as human shields.
US secretary of state John Kerry launched his European visit aimed at shoring up support for military action in Syria.
He is due in London today for talks with Foreign Secretary William Hague in the wake of the vote by MPs against the action.
European Union foreign ministers meeting in Lithuania backed the need for a "clear and strong response" to the use of chemical weapons after hearing Mr Kerry's case.
But in a joint statement, member states stopped short of endorsing any US-led strike, stressing "the need to move forward with addressing the Syrian crisis through the UN process".
President Barack Obama will address his nation on Tuesday as he battles to secure the backing of Congress for the use of the American military for a punishment strike on Assad's government.