One of the 11 terrorists behind the Paris massacre is believed to have visited London and Birmingham earlier in 2015 to meet the suspects of the attack, counter-terrorism officials said.
According to The Guardian, he managed to enter the United Kingdom, travelling to London and Birmingham, before slipping away again to continental Europe, despite a heightened terrorism alert.
In both cities he met people who are suspected of having the intention and capability of plotting or assisting terrorist activity against the UK.
However, it is not yet known how he got into the UK.
The British-based suspects he visited are under investigation by MI5 and police counter-terrorism units.