More than half (54 per cent) of terror plots in Germany have involved asylum seekers and refugees since 2014 and the onset of the migrant crisis.

The report, by the Heritage Foundation think tank, found that attacks across Europe by foreign trained militants increased dramatically in 2016, following the height of the migrant influx, with Germany becoming a much more popular target.

“The increase in the threat to Germany is especially stark,” the report’s authors write. “There were no plots in Germany in 2014, and only two in 2015. In 2016, this increased eightfold.

“There is a straightforward reason for this: In 2015, Germany took in over 1 million refugees and 2016 saw a surge in plots involving refugees.”

Plots in Germany comprised just 5 per cent of those in Europe in 2015, shooting up to 27 per cent in 2016. In fact, the nation faced more plots in 2016 alone than in the decade and a half between 2000 and 2015, with civilian rather than government targets most common.

In total, 142 Islamism plots claimed 300 lives and more than 1,000 casualties, in 15 European nations, over the 29-month period studied by the think tank.

Across the continent, around 15 per cent of the plots (142) featured refugees and asylum seekers, implicated in either planning the attacks alone or as part of a larger cell.

The migrant planned attacks struck nine separate European countries, but mainly targeted Germany (12 of the 22 plots).

In 2014 and 2015, there were just three plots by foreign trained attackers in Europe, all linked to Iraq, with the most prominent example being the Paris attacks.

In 2016, however, the continent was struck by 16 such plots by migrants and foreign fighters, 11 targeting Germany.

German Chancellor Angela Merkel suspended the Dublin regulations and effectively opened the nation’s borders in 2015. Since then, Germany has taken far more migrants than any other European nation.

Before 2016 – the year after around a million asylum seekers poured into the nation – Germany was not targeted by those trained abroad, with France and the UK facing the most attacks of this nature, the report explains.

Yet, during 2016, 60 per cent of all plots in Germany were conducted or planned by foreign trained militants, all of whom had fought or trained in Syria.

In 15 of the 22 (68 per cent) plots hatched in Germany since 2014, one of the cell’s perpetrators was in direct contact with a foreign terror group.

This is disproportionately high when compared to rest of the continent, in which only 64 of the 142 plots (45 per cent) had one or more members known to have been in contact with such groups.

“The main source of this threat is from the Islamic State of Iraq and al-Sham (ISIS), which has taken advantage of the refugee crisis in order to smuggle its operatives into Europe,” the report’s authors explained.