Police in London are appealing to passengers to be pro-active in reporting anything suspicious.
If you think you have seen a person acting suspiciously, or if you see a vehicle, unattended package or bag which might be a threat, immediately move away and call 999.
The terrorist threat remains real and there is no room for complacency. The public should remain alert and aware of their surrounding at all times. If something strikes you as suspicious and out of place then trust your instincts and call the police.
Anti-Terrorist hotline: 0800 789 321
If you suspect it, report it - Police renew call for vigilance against terrorists
London Prepared - government website showing how London is prepared for terrorist threats