A report today says British police and security agencies are keeping tabs on 30 terror plots, Home Secretary Jacqui Smith told a Sunday newspaper.
"There are 22,000 individuals who are being monitored. There are 200 networks involved and 30 active plots," Smith said in an interview with the News of the World.
"We now face a threat level that is severe. It's actually growing," said the interior minister. "We can't wait for an attack to succeed and then rush in new powers. We have got to stay ahead.
"Because we now understand the scale of what is being plotted, the police have to step in earlier, which means they need more time to put evidence together."
In 2005, four British suicide bombers killed 52 people on underground trains and a bus in London. Other attacks have been foiled by police. Eight men are currently on trial in London accused of trying to blow up transatlantic jets using liquid explosives in 2006.
"Since the beginning of 2007, there have been 57 people have been convicted on terrorist plots," said Smith. "Nearly half of those pleaded guilty so this is not some figment of the imagination. It is a real risk and a real issue we need to respond to."
The minister also confirmed she would announce a scheme next week to bring over moderate Islamic clerics from Pakistan to assist British imams in combating extremism in their communities.
"The vast majority of British Muslims have a Pakistani heritage. If we work with the government there we can win the arguments," said Smith, who visited Pakistan this month.