An email I received yesterday from a veteran aid worker and friend summed up the latest unfolding humanitarian crisis in Syria in one word: “terrifying”.

Upwards of 21,000 newly displaced people are said to have recently arrived near the Turkish border fleeing the latest onslaught of airstrikes, military offensives and shifting frontlines.

All this comes as world leaders opened a donor conference in London for Syria, and UN brokered talks in Geneva were halted amid acrimony between Syrian government and opposition negotiators after only two days.

There is simply no avoiding the fact that Syria’s humanitarian needs far from improving are getting increasingly dire by the day.

Lately we’ve heard a lot from those whose sole cry is ‘enough is enough’ when it comes to providing sanctuary for refugees. By and large these are the same people who advocate the need for more razor wire fences and the confiscation of refugee assets.

How much more productive it would be if these same people devoted half as much energy to addressing the humanitarian needs of Syria’s displaced and building the case for a coordinated and negotiated resolution to the war. That said, we are where we are, and it is not a good place. Let’s just remind ourselves of what this means in human terms.

Right now an estimated quarter of a million people have been killed, six million Syrians displaced within the country and another four million made refugees scattered across Jordan, Lebanon, Turkey and beyond.

In response to the deteriorating situation UN agencies are appealing for $7.73 billion to cope with the disaster that is looming this year and a further $1.2 billion to fund national response plans by the countries in the region.

Any financial aid is of course welcome. But let’s not forget that for many European nations, improving the humanitarian situation in Syria and neighbouring countries is motivated in great part by reducing incentives for Syrians to travel to Europe. Yesterday at the donor conference in London, Prime Minister David Cameron said as much.

"We can provide the sense of hope needed to stop people thinking they have no option but to risk their lives on a dangerous journey to Europe," said Mr Cameron, announcing a new UK pledge of 1.2 billion pounds.

Even the staunchest of Cameron supporters would be hard pressed to deny that throwing money at the problem is aimed largely at keeping Syria’s displaced inside Syria or as close to home as possible.

And this brings me to the situation inside Syria itself.

What one wonders does the Prime Minister make of the call by besieged Syrians in an open letter to the London conference for the UN to deliver life-saving aid by any means necessary?

"We know that the money you raise today in London is unlikely to reach us or alleviate the suffering in our besieged areas," was the stark conclusion of local coordinators inside such areas.

According to the global advocacy group The Syria Campaign among those who have voiced such concerns are rescue workers from the Syrian Civil Defence (also known as the White Helmets), field hospital doctors, representatives of women's groups and relief volunteers. In a letter to the leaders of the UK, Germany, Norway, Kuwait and the UN - who are hosting the London conference, these local coordinators made clear their fears that money raised will fail to get to those that need it most.

In short, what such volunteers and activists are saying is that while money donated by the UK government and others is welcome, there must also be pressure applied on the UN to ensure such aid is actually delivered. If necessary they say by breaking sieges of towns and cities or coordinating airdrops.

These are Syrians at the sharp end of the humanitarian crisis speaking and for that reason alone need to be listened too. For the UN to undertake such operations of course is easier said than done both politically and logistically.

This not least as the Syrian government intensifies its assault on cities like Aleppo. Indeed the suspension of the UN brokered talks in Geneva came only hours after Russian Foreign Minister Sergei Lavrov delivered a blunt message to the peacemakers seeking to silence the guns in Syria.

Lavrov made it clear that Moscow, which has provided extensive military assistance to Syrian President Bashar al-Assad, has no intention of pausing its offensive of airstrikes in the rebel-controlled areas around the cities of Aleppo and Homs.

The Russian proclamation underlines one of the key weaknesses of the US and Russian-backed Syrian peace process. Any political settlement to the country’s civil war will not require that the combatants halt their fight against terrorists. And on that subject there’s no consensus about which of the many armed groups fighting in Syria should fall into that category.

All this does not bode well for humanitarian efforts on the ground.

Simon O’Connell, is Europe Executive Director of aid agency Mercy Corps which has its European headquarters in Edinburgh. Mercy Corps was one of only two international organisation representatives invited to the ‘Inside Syria’ plenary session at yesterday’s London conference.

O’Connell’s assessment summed up the challenges those within the humanitarian community face and how only a reduction in violence will allow them to make a difference.

“As airstrikes escalate and front lines shift, innocent Syrian civilians are repeatedly forced to flee and are struggling to find safe places… we expect to see these numbers, along with the number of civilian casualties, rise if nothing is done to stem the violence.”