Three terror attacks have been prevented in the UK since the coronavirus pandemic began, according to security services.

Arrests for terrorism-related activity fell by 34% in 2020, the lowest level in nine years, Home Office data showed. But the number of terror plots stopped has risen to 28 since March 2017, counter terror police said.

A senior officer warned: « Terrorists have not stopped planning attacks or radicalising vulnerable people online. »

Deputy Assistant Commissioner Dean Haydon said officers had made « 185 arrests across more than 800 live investigations – stopping three possible terror attacks in the process ».

The senior national coordinator for Counter Terrorism Policing said that as lockdown eases « there will be greater opportunity for terrorists to operate ». « We want the public to join the police, security staff and retail workers in a collective community effort to minimise the chance of attack, » he said.

In February, the UK’s terrorism threat level was downgraded from « severe » to « substantial », which means means an attack is still likely.

Mr Haydon also warned of a « worrying trend » of children under the age of 18 being arrested for terrorism-related activities. This age group was the only one that saw an increase – rising from 11 to 17 in total, Home Office data showed. « That is a total of 10% of all arrests, which has risen from just 4% in the previous 12 months, » said Mr Haydon.Police have launched a website and helpline to offer advice and support for families to prevent young people becoming involved in terrorism, he said.