British security forces are monitoring “another great plot,” the country's counter-terrorism minister has warned.

Lord Alan West said during a House of Lords debate Tuesday that despite taking action to improve security, Britain still faced a huge threat from violent extremists.

The country's threat level is listed by the domestic intelligence service MI5 as severe — the second-highest of five levels.

“The threat is huge. It dipped slightly and is now rising again within the context of ‘severe.’ There are large complex plots. We unraveled one, which caused damage to Al Qaeda and the plots faded slightly,” Lord West said.

“However, another great plot is building up again, which we are monitoring.”

He gave no details on the plot, and the Home Office refused to comment.

Lord West, the former head of the Royal Navy, was speaking after Prime Minister Gordon Brown's Government withdrew plans yesterday to extend the time suspected extremists can be held without charge from 28 to 42 days.

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