Syrian President Bashar al Assad has been shamed in Parliament for his regime's alleged use of starvation as a 'weapon of war'.
International Development Secretary Justine Greening said she was calling for immediate access for aid agencies to settlements across the war-torn country as well as the town of Madaya so that 40,000 people can receive food packages with up to a month's supply.
It has been reported that people may be dying from starvation in the town, and photographers at the scene have captured images of clearly malnourished children.
Ms Greening has now warned the Assad regime to abide by UN law, which states that the organisation should not have to negotiate access across territory to deliver aid.
Her strong message came in her answer to an 'urgent question' tabled by MP for Batley and Spen Jo Cox on what the Government's response is to the crisis.
Ms Greening said: "No-one who has seen the pictures coming out of Madaya over recent days can say this situation is anything other than utterly appalling. And this atrocious situation is deliberate and it is man-made.
"The Assad regime has besieged this town since July causing horrific suffering and starvation."
"Across Syria Assad and other parties to the conflict are wilfully impeding humanitarian access on a day by day basis. It is an outrageous, unacceptable and illegal mechanism to use starvation as a weapon of war.
"So right now I call on the Assad regime and all parties to the conflict to allow immediate and unfettered access to all areas of Syria and not just Madaya."
Ms Cox, an aid worker for 10 years and previous head of policy for Oxfam, said: "It should not have taken an international outcry of this scale to have agreed what is actually a nominal agreement on access to just one small community, 40,000 out of what could actually be up to 1m people currently living under siege inside Syria."
"It is the Assad regime that are primarily responsible for this policy of sustained, systematic starvation by the population of Syria.
"Of the areas under siege, 52 are under Assad control, two under rebel control and one under the control of Isis.
"Let's be clear he is responsible for 99% of those under siege."
She asked the Government to demand answers from the UN on why they hadn't 'pushed the envelope' hard enough to gain access, when they have clear permission to do so under UN resolution 2165.
Food drops carried out by the RAF should be the next consideration if the UN fails to negotiate better access for besieged communities, she added.
The International Development Secretary said: ""I can simply assure her that everyone working on this crisis has no other thought in mind other than getting to all the people who are desperately in need which is why we condemn utterly the fact that international humanitarian law is being routinely broken."