More than 350 convicted and suspected terrorists have been freed from prison over the last seven years, as latest figures also reveal the number of suspects arrested by police has also dropped 20 per cent in the last 12 months.
There were 41 convicted terrorists released from jail in the year to June as well as 12 suspects who had been held in custody but not sentenced, according to the Home Office.
Overall, 353 terror criminals and suspects have been released from prison between June 2012 and the same period in 2019, of which 245 were convicted of offences.
According to the Home Office figures, the number of people arrested for terrorism offences has fallen. There were 259 people were detained for terrorism-related activity in the year ending September 30, compared with 325 arrests in the same period in 2018.
Of these, 96 were released on bail or released under investigation - meaning they were not subjected to any restrictions while enquiries into the offences continued.
There were 88 charged and 62 of these were for terrorism-related offences.
A further 14 received a caution, were recalled to prison or handed over to immigration authorities and 60 suspects were released without charge.
The figures come less than a week after the London Bridge terror attack which claimed the lives of Saskia Jones and Jack Merritt.
Convicted terrorist Usman Khan embarked on a killing spree while attending a prisoner rehabilitation programme at Fishmongers' Hall last Friday afternoon.
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The 28-year-old, armed with two knives and wearing a fake suicide vest, was tackled by members of the public, including ex-offenders from the conference, before he was shot dead by police.
Khan, a British national from Staffordshire, was released from prison on licence in December 2018, halfway through a 16-year prison sentence after he was convicted of terror offences in February 2012.
He was part of an al Qaida-inspired terror group - linked to radical preacher Anjem Choudary - that plotted to bomb the London Stock Exchange and build a terrorist training camp on land in Pakistan-controlled Kashmir owned by his family.
While the number of terrorism-related arrests and convictions has declined, the number of attack plots foiled by police and the security services continues to rise.
Counter Terrorism Policing’s Senior National Coordinator, Deputy Assistant Commissioner Dean Haydon said: “When we consider these latest statistics, we should also remember that Counter Terrorism Policing and UK intelligence services have foiled 25 attack plots since March 2017.
“We are also running more than 800 live investigations across the country, a record high.
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"I would urge everyone to remain vigilant and ACT if you see anything suspicious by reporting it to us confidentially.
"The public are playing a crucial role in helping police and the security services disrupt terrorist activity, with more than 22 per cent of all reports from the public producing intelligence which is helpful to police."
Humberside Police has this week revealed how it is working with counter terrorism police to make sure ports in the area are not exploited by terrorist and organised crime groups.
Project Scimitar sees police officers working alongside representatives from numerous agencies to conduct proactive visits aboard vessels, regular days of action and high visibility patrols through the port areas.
Superintendent Matt Davison, Regional Protect and Prepare Lead for Counter Terrorism Policing North East, said: “Protecting our borders is a significant challenge and initiatives such as this, where we can work closely with our multi agency colleagues to maximise our efforts, maintain security and identify vulnerable individuals is vital in our ongoing work to protect the public.
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“The maritime communities visiting UK and international Ports are the eyes and ears of Project Scimitar. We are encouraging everyone to be alive to things that may be suspicious or just not seem right and make a report to police or Crimestoppers.
“This includes concerns around terrorism, people trafficking, the exploitation of migrants and low wages, as well as potentially suspicious behaviour of people or vehicles.
“By reporting concerns about potentially suspicious activity or something that just doesn’t seem right they can help keep the Humber Ports safer for everyone. You are not wasting our time in making a report. Information is assessed and appropriate action taken by the most suitable agency.
"Whilst in isolation your information may not seem significant, it is possible that, in conjunction with other information, it could help tackle terrorism, crime or protect vulnerable people.”