LONDON: The UK’s domestic intelligence agency thwarted a plot by an Islamist extremist to attack a music festival attended by about 90,000 people every year, Mail Online reported.

In 2022, a tipoff led M15 officers to arrest a 15-year-old boy suspected of preparing an attack at the Isle of Wight Festival. It is claimed the boy was inspired by Daesh and researched weapons online, The Sun reported.

It comes after counterterrorism police this week revealed that they had foiled 39 recent terror attempts, including planned attacks on politicians.

“The threat of a mainland terror attack of scale is still an active and live threat,” a security source told Mail Online.

The source added that the locations targeted are “carefully planned to cause maximum damage.”

In a separate case, MI5 also surveilled and captured 19-year-old Matthew King, who plotted to attack an army barracks and magistrates’ court.

He was sentenced to life in prison after MI5 officials acted on intelligence provided by the Prevent strategy.

King, from Essex, wanted to join Daesh in Syria. He expressed a desire online to kill a Royal Marine and other targets with woman identified in court as Miss A.

He received a discretionary life sentence with a minimum term of six years after admitting preparation of terrorist acts.

“I genuinely believe this was an imminent terrorist attack,” Met Police Counterterrorism Command chief Dominic Murphy told The Sun.