London (CNN) -- British Prime Minister David Cameron opened an emergency debate on Syria Thursday, calling it an issue of how to respond to one of most "abhorrent uses of chemical weapons in a century."
But he also acknowledged the views opposing a military intervention.
"This deep public cynicism imposes particular responsibilities on me as prime minister to try and carry people in the country and in this house with me," said David Cameron.
"Our actions won't be determined by my good friend and ally the American president, they will be decided by this government and votes in this House of Commons."
Cameron asked: "Is Britain a country that wants to uphold that international taboo against the use of chemical weapons? And my argument is: Yes, it should be that sort of country."
He also urged those present to watch the disturbing video footage of the victims of the chemical attack. "You can never forget the sight of children's bodies stored in ice, young men and women gasping for air and suffering the most agonizing deaths, and all inflicted by weapons that have been outlawed for nearly a century."
Former foreign secretary Jack Straw wondered how the use of chemical weapons would be degraded without a mass invasion.
"Since you're not proposing that, say what your objective would be in terms of degrading the chemical weapons capability," he said.
The prime minister said that any action could not come with a guarantee.
"How can we be certain any action will work? How can we be certain any action would not have to be repeated? Frankly, these are judgment issues -- thve only really firm judgment I think we can all come to is that if nothing is done we are more likely to see more chemical weapons used."
Concern for neighbors
Keith Vaz, Labour chair of the Commons Home Affairs Select Committee aired his concerns about the effects on neighboring countries:
"Has he [David Cameron] looked at the consequences of what might happen with intervention and the effects that it will have on a country like Yemen?"
The Prime Minister replied: "Our Nato ally Turkey has suffered terrorist attacks and shelling from across the border, but standing by as a new chemical weapons threat emerges in Syria is not going to alleviate those challenges, it's going to deepen them."
Opposition leader Ed Miliband expressed his disagreement with the prime minister that intervention would not affect the government's position on Syria. "I've got to say to you [David Cameron], with the greatest respect, that's simply not the case. For me, that does not rule out military intervention.
"We should also have in our minds the duty we owe to the exceptional men and women of our armed forces and their families who will face the direct consequences of any decision that we make."
Lessons from Iraq
The opposition leader also reflected on Iraq. "I am very clear about the fact that we have to learn the lessons of Iraq," he said. "Any action ... must assist this process and not hinder it."
Echoing the prime minister's earlier sentiments, former foreign secretary Sir Malcolm Rifkind warned parliament about the messages that may be given out to the Syrian government.
"At this very moment, the Assad regime in Damascus are watching very carefully as to whether they will get away with what they have done," he said.
"If there is no significant international response of any kind, then we can be absolutely certain that the forces within Damascus will be successful in saying we must continue to use these whenever there is a military rationale for doing so.
"There is no guarantee that a military strike against military targets will work, but there is every certainty that if we don't make that effort to punish and deter, then these actions will indeed continue."