Police disclosed the information as Home Office figures showed the number of arrests for terrorism-related activity fell by 34%, the lowest level in nine years.
Despite this, the number of terror plots stopped has risen to 28 since March 2017, counter terror police said.
Deputy Assistant Commissioner Dean Haydon, the senior national co-ordinator for Counter Terrorism Policing, said: “These statistics tell me two things.
“Firstly, that despite facing unprecedented challenges brought about by the pandemic, Counter Terrorism Policing continued to keep the public safe by making 185 arrests across more than 800 live investigations – stopping three possible terror attacks in the process.
“And secondly, that while the rest of us have been focused on protecting ourselves and our families from this terrible disease, terrorists have not stopped planning attacks or radicalising vulnerable people online.”