LONDON - The number of people convicted for terrorism offences in Britain rose to the highest level since data collection began in 2009, figures published on Thursday showed.

Britain is on its second-highest threat level - "severe" - meaning an attack is considered highly likely. Last year there were five major incidents classified as terrorism in which 36 people were killed.

A total of 90 people were convicted of terrorism offences in the year to 30 June 2018, police said. However, the number of terrorism-related arrests fell by 22 percent from 449 to 351.

"We’re not only successfully prosecuting more people than ever before, but we’re also jailing the most dangerous offenders for longer - helping to keep the public safe," said Police Deputy Assistant Commissioner Dean Haydon.

(Reporting by Guy Faulconbridge; editing by Michael Holden) ((guy.faulconbridge@thomsonreuters.com; 07825218698;))