UK police say have made a significant arrest following London subway train station explosion

The British police say they have made a significant arrest following a Daesh-claimed bomb explosion at a London subway train station.

According to the police, they have arrested an 18-year-old man in the southern port city of Dover under terrorism act. Britain has already beefed up security following Friday’s blast.

There has also been an increased presence of military troops in the capital.

This as security forces are still investigating the incident, which left nearly 30 people injured.

Officials say an improvised explosive device triggered the blast. Reports say the device had a timer.

Meanwhile, Prime Minister Theresa May has announced that the national threat level has been raised to critical from severe.