UK terror arrests nearing record levels

The figures include 12 arrests made after the Westminster attack, in which five people were killed

The UK is heading for a record number of terrorism-related arrests amid massive investigations into three attacks.

New figures show that in the year to March 2017, police arrested 304 people - up a fifth on the previous 12 months.

Combined with those held since March, it means this year's total may top the previous record of 315, set in 2015.

The figures include the dozen held and later released without charge during the Westminster Bridge investigation.

But they don't include those held since the Manchester or London Bridge attacks.

More than 40 people have been held in relation to both of those incidents - with all 22 arrested in Manchester released without charge.

Those arrests, alongside at least 20 further arrests across England since March, indicate that the rate of police operations has been increasing.

It means 2017 will almost certainly be a record year.

Conviction rate

Of the 304 arrests to the end of March, 108 resulted in a charge - and 91 of those were charged with a terrorism-related offence.

Nine out of ten of those who ended up in court were convicted - and figures show they are receiving longer sentences than ever before.

Of those that remained, 88 were bailed pending further investigation and 100 were released without charge.

Eight others faced "alternative action"- meaning they may have been detained because they were mentally ill, recalled to prison, or handed over to border officials for deportation.

As of March 2017, there were 186 people in prison for terrorism-related offences - up 15% on the previous year.

Three-quarters of those arrested were classed as being suspected of involvement in "international terrorism" - meaning activity relating to jihadist groups.

Some 16% were classed as being suspected of involvement in domestic extremism - typically meaning neo-Nazi style activity.