BBC said:Seven people have been detained by police and Immigration Service officers under powers allowing deportation for national security reasons.
Six were held in London and one in Greater Manchester.
Sources said all the detainees were Algerians and the majority were among the eight men cleared in April of involvement in a ricin poison plot.
The home secretary said he ordered the raids following "detailed submissions" from the police and security services.
Full story here with appeal for witnesses from the BBC.
The following may have nothing to do with terror. Just weird.
BBC said:A man has shot himself dead on the M1 after a high-speed chase by armed police in the early hours of Thursday.
South Yorkshire Police say officers fired a baton round at the suspect who then turned his gun on himself.