The UN says the victims of the conflict have now fled war and persecution and become refugees in neighbouring countries, making the Syrian conflict the UN refugee agency's worst crisis for almost a quarter of a century.
"Put pressure on your local MPs, put pressure on the government to push for a solution to this conflict, we have to show solidarity with those innocent civilians who are trying to get on with their lives," said Louise Finan, emergency advocacy officer - Syria & Iraq with Christian Aid on Premier's News Hour.
Latest figures from UNHCR released on Thursday, put the total number of refugees from Syria to just over 4,013,000 people.
UNHCR said in a statement that the new figures were based on new arrivals in Turkey and updated data from the authorities on refugees already in that country.
At least an additional 7.6 million people are displaced inside Syria -- many of them in difficult circumstances and in locations that are difficult to reach.
The four million figure is made up of 1,805,255 Syrian refugees in Turkey, 249,726 in Iraq, 629,128 in Jordan, 132,375 in Egypt, 1,172,753 in Lebanon, and 24,055 elsewhere in North Africa.
