The British Government's Christmas message of solidarity with persecuted Christians is a welcome gesture, but for many communities around the world time is quickly running out.

There is no country where this is more acute or tragic than Iraq, home to one of the oldest Christian communities on earth but which has, since the fall of Saddam Hussein, undergone its own Calvary.

Three years ago, I spent Christmas in snowy village of Sarsing in the north of the country. The Christians here are Assyrian, a distinct ethnic group who speak Aramaic, the language of Christ, and who trace their conversion back to the very earliest days of the faith. The town lies on a cliff, close to one of the highest points of Iraq, and is a reminder of their tragic past, founded a century ago by survivors of the Assyrian Genocide (1914-1923).

The Assyrians survived to become part of the new Iraq but they may not endure much longer. Sarsing's co-mayor, Isaac Yaqo, keeps a record of every single Assyrian who leaves the town, in a small, weathered black book where he writes their names, their ages, and the dates they fled the country. Yaqo calls it his "blacklist", and is unforgiving of those who he feels have abandoned the town, because, he says: "Leaving means you're giving up on our cause".

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When I last visited in 2016, he showed me the book, nearly all its pages filled. At that time, the mayor said, there were 118 Assyrian households remaining in Sarsing, compared to upwards of 300 in 2014, while Kurdish households now numbered more than 2,000. I spoke to Yaqo by phone the other day; the number of Assyrian households was now down to 92.

"Christmas has been difficult in recent years," he said. "I go to church and I'm reminded of everyone who is no longer here. It's a pain that is difficult to describe."

Nearby is the Nineveh Plain, where in 2014 the world watched as ISIS swept through the region, daubing the homes of Christians in a horrific echo of past genocides. Kurdish forces pledged to defend minorities before tactically withdrawing as ISIS approached, a decision which has left a deep severance of trust.

Today, around half of the displaced Assyrian population has returned home following the end of the ISIS occupation, and locals live with daily reminders of the terror group, each day passing with uncertainty. At Christmas this year most Assyrians will quietly attend Mass in either dilapidated or partially renovated churches, although many ancient monasteries and churches were completely destroyed. Rehabilitation efforts are underway, but it will be a long time before the stain of the Islamic State is lifted from these lands.

The events of 2014 created a security vacuum filled by a variety of actors pursuing competing agendas. Kurdish claims to this territory, often advanced at the expense of minority peoples like Assyrians and Yazidis, have generated resentment towards the KRG and its politicitised peshmerga militias. Alongside Kirkuk and Sinjar, the Nineveh Plain is disputed between the Baghdad central government and the Kurdish regional government in Erbil; this ongoing dispute has proved disastrous for the various minority groups caught in between.

The situation is even worse to the south. This year religious leaders canceled public Christmas celebrations in Baghdad as an act of solidarity with protestors, but in the Iraqi capital the country's devastated minority have barely been able to mark the birth of Christ since the ill-fated 2003 invasion.

The ensuing sectarian war between Sunni and Shia, and the breakdown of central authority, left the country's Christians -- a mixture of Eastern, Catholic, and Orthodox denominations -- at the mercy of Islamist militias and kidnaping gangs. Once a sizeable minority, Iraq's Christian suffered a sickening wave of attacks, with over 60 church bombings in Baghdad and Mosul and more than a thousand sectarian murders. Hundreds of thousands fled abroad.

In 2008 Baghdad held its first-ever public Christmas celebration, sponsored by the Iraqi Interior Ministry as part of widespread efforts to root out sectarian violence and improve the country's image. A spokesperson was quoted saying, "All Iraqis are Christian today!" but the following year the celebrations were cancelled amid widespread threats to bomb churches on Christmas Day. Then in October 2010 came the most appalling attack of all, carried out by the Islamic State of Iraq -- the forebears of ISIS -- who murdered almost 50 worshippers at the Our Lady of Salvation Church in Baghdad.

But the terror would not end there, and in 2013, 38 people were killed in a series of bombings targeting Assyrian areas in Baghdad, including a car bomb placed outside a church and aimed at worshippers leaving a Christmas service.

Today there are few Assyrians left in Baghdad to attend Mass, and most avoid churches and holy sites on major holidays. Where they are held, Christmas services are abbreviated and no one lingers afterwards. In Jordan I had met a woman named Rita, who had fled Baghdad in 2015 and recalled: "If we were in public, only the brave ones would dare to whisper: 'Merry Christmas.'"

Yet everywhere in Iraq, Christians are leaving. While the Kurdish Regional Government is often lauded for its treatment of minorities, the unceasing emigration of Assyrians from its administrative areas points to a different reality on the ground.

Indeed, entire Assyrian villages in the Kurdistan region have emptied in recent years, driven by crushing socio-economic factors, political repression and forced demographic change. While Kurdish officials point Western politicians and journalists to new churches erected in the region as a sign of prosperity and tolerance, in reality Assyrian families are silently packing their bags to leave.

In the northern Nineveh Plain lies a small village called Garmawa which, like Sarsing, was founded by survivors of the Assyrian Genocide over the site of a previous Assyrian village abandoned a century earlier. Garmawa is home to 80 Assyrians who mostly adhere to the Ancient Church of the East; for them, Christmas this year is a deadline.

Ownership deeds to Garmawa and the agricultural lands that surround it were acquired by a non-Assyrian man in the 1940s, since when the villagers have farmed the lands and made payments to the landowner -- and his descendants -- either with cash or a fixed portion of their product, or a combination of the two. They harvest all sorts of crops, including wheat, barley, rice, melons, and olives, and their produce is bought by the Iraqi Government, although the authorities haven't paid in full since the rise of ISIS.

Today, Garmawa's 247 acres of land are up for sale with a massive $2 million price tag. With their own livelihoods and the future of their community at stake, locals are fearful of change -- because for Assyrians, change in Iraq has usually led to more suffering.

And what happened in nearby Sarsing does not offer much hope. Here, following the horrific Anfal campaign against the Kurds, agricultural lands were used by the KRG -- with the consent of local Assyrians -- to house survivors. No strangers to the horror of genocide, the Assyrians welcomed the refugees into their town with the understanding that their stay was temporary -- but it didn't turn out that way, and former guests became landlords seemingly overnight.

Assyrians also suffered from Saddam's Arabisation campaigns. In the nearby town of Tel Keppe, Sunni Arab populations were relocated to lands outside the historic city core, and their numbers soon dwarfed the Assyrians, many of the original inhabitants forced to sell their properties. There will be no Christmas services in the town of Tel Keppe this year, as too few Assyrians returned after ISIS. Millennia of Christianity simply vanished.

Desperate to regain control over their fate, residents of Garmawa have appealed to the Assyrian diaspora in the US, Australia, Sweden and elsewhere. When a neighboring Assyrian town called Ein-Baqreh went up for sale some years ago, the land was purchased by Assyrian investors, so residents of Garmawa hope that their town might be saved, too, and have even set up a GoFundMe -- but it looks like it may be too little, too late. Their future is slipping away.

"We don't want to leave," local resident Zaya told me. "My grandfather lived in this home and farmed these lands. This land belongs to Assyrians -- we built this town from nothing and brought it to life."

But this Christmas, even more so than in recent years, Assyrians across Iraq carry the weight of uncertainty about their future in this ancient land. "To know that there is next to nothing we can do to guarantee our very existence here is painful," Zaya reflected.

Those who plan to celebrate will mark the holiday by attending Mass, exchanging gifts, making traditional date-filled cookies called kileche, and wondering whether this will be their last ever Christmas in their homeland.