While it no longer controls vast swathes of Iraq and Syria, Islamic
State remains a threat and will seek to spring 10,000 of its fighters
from Syrian prisons in 2023, experts say.
The infamous terror
group is much diminished from its peak in 2014 but it remains a menace
in a volatile part of the Middle East, as well as abroad in Afghanistan
and parts of Africa.
What is more, there are fears that a possible ground offensive by
Turkey in Syria could create the perfect conditions for IS to once again
seize power.
"Blink and you'll miss it and suddenly ISIS will be back," says Middle East expert Dr Shiraz Maher.
In a year where other stories have dominated the headlines, Sky News looks into what IS has been doing, and whether huge tracts of territory could once again fall under its flag.
Since its last bastions in Syria fell to Western-backed forces, IS has been operating at a "greatly diminished" level, according to terror expert Matthew Henman.
He said: "But the level of threat, the level of operational activity, has stayed reasonably consistent over that kind of period.
"In various key theatres the group has maintained a steady tempo of insurgent violence."
Mr
Henman, who works for the Janes intelligence agency, said the group and
its affiliates further afield are focused on exploiting regional
instabilities and still have designs on seizing territory.
Seeking to seize territory in parts of Africa
Several
branches, or provinces, of IS exist across the Middle East and Africa.
Each has its own regional leader who then pledges allegiance to the
overall IS leader.
At
its height the so-called IS caliphate held sway over about a third of
Syria and 40% of Iraq - a territory larger than Iceland.
In recent
years much of the groups focus has turned to west Africa, Mr Henman
says, where it has been met with multinational taskforces seeking to
stop it gaining a proper foothold.
In Afghanistan the group's
regional affiliate - known as the Islamic State in Khorasan Province -
has increased its attacks since the Taliban regained power.
Earlier this month, China advised its citizens to leave the country
following a co-ordinated attack by Islamic State militants on a
Chinese-owned hotel in the heart of Kabul.
But the danger of IS activity in Iraq and Syria remains, despite its diminished presence.
Some
70,000 people with suspected links to the group, including women and
children and around 10,000 IS militants, are being held by Kurdish
forces in northeast Syria.
Dr
Shiraz Maher, a senior lecturer at King's College London, says the risk
of IS freeing thousands of imprisoned fighters is the "single greatest
security threat to the West".
He told Sky News: "The Syrian
Democratic Forces have repeatedly said that this is a ticking time bomb
that they are sitting on (that) they are not capable of dealing with
themselves alone."
Many of those being held by SDF forces are foreign fighters, but many nations have been reluctant to deal with them.
The
delicate situation could be put at risk if Turkey carries out its
threat of a land invasion targeting Kurdish forces, Dr Maher warned.
Such
a development may force Kurdish authorities to divert resources
currently guarding its network of detention centres to the front line,
creating a "massive ability" for IS to free its supporters.
"We
need to think creatively and have some courage in dealing with this
issue and nipping it in the bud right now," Dr Maher said.
"If ISIS return to Syria and Iraq, people will die on the streets of Berlin, London and Madrid."