An eighteen year old man has been arrested in Dover in connection with yesterday's bomb attack on a London Underground train.
He's being held on suspicion of a terror offence after 29 people were injured at Parsons Green station.
The UK's terror threat level has been raised to its highest and extra police officers are being deployed across the country.
Sky's Enda Brady is at Scotland Yard.
These people getting back on the underground at Parsons Green today are defiant: