Terrorism is the use of indiscriminate violence to spread fear in a bid to achieve political, religious, ideological, or financial aims.

There have been various causes of terrorism in the UK. In the 20th century, most attacks were linked to the Northern Ireland conflict. Since the 2000s, most terror attacks have been linked to Islamic extremism.

MI5 and police are running more than 500 live operations involving roughly 3,000 potential suspects at any one time.

There were 166 arrests for terrorism-related activity in the year ending 31 March 2021, 98 fewer than in the previous 12-month period (a fall of 37%).

The total number of arrests initially fell in the late 2000s, reaching a low in 2011. They then increased until 2018. Since 2018, arrests have fallen again, and in 2021 are now below the average for the entire time series.

Are terrorist attacks in the UK on the rise?

According to Statista, between 2000 and 2019 the three years with the highest number of terrorist attacks in the UK all occurred relatively recently, in 2014, 2015, and 2017. Although 2019 saw a drop in the number of attacks compared with these years, the 64 attacks recorded in that year is still far higher than the relatively low number of attacks that happened between 2002 and 2013.

From 1970 to 2019, there were 3,416 terrorist-related deaths in the UK, the highest in Western Europe.  However, most of these happened within Northern Ireland, and since the Good Friday Agreement was signed in 1998, the numbers of deaths from terrorism has reduced markedly. Since 2001, there have been around 100 deaths from terrorism in Britain.

Since 1970 the worst terrorist attack in the United Kingdom was the downing of Pan Am Flight 103 in December 1988 above Lockerbie, Scotland, which caused 270 fatalities. Of the ten attacks worst terrorist attacks in the UK, seven were related to the troubles in Northern Ireland while two were linked to Islamic extremism, including the Manchester Arena bombing of 2017.

It is important to remember that the likelihood of you being caught up in a terrorist attack remains very small, but it’s still good to be vigilant.

Click here to find out more about some of the signs that terrorist activity may be being planned near you, and what to do about it.