The piece of aircraft wing that washed up on the island of Reunion last week is from flight MH370, it has been confirmed.

Malaysia’s Prime Minister, Najib Razak, addressed his citizens in the early hours of Thursday morning to say that investigators have now “conclusively confirmed” that the flaperon is part of the Malaysia Airlines Boeing 777, which went missing in March 2014.

“We now have physical evidence that… flight MH370 tragically ended in the southern Indian Ocean,” the PM said in a live TV broadcast.

“The plane’s disappearance was without precedent. At every stage we followed the tiny amount of evidence that existed. But, despite the efforts of 26 nations and the largest search in aviation history, from the South China Sea to the Indian Ocean, the plane could not be located.”

He added that questions remained as to “why MH370 veered off course and went dark”. But the discovery of this first piece of solid evidence after 17 months of searching raises hopes that the mystery may now start to be unravelled.

Flight MH370 was carrying 239 passengers and crew from Kuala Lumpur to Beijing when it disappeared from radar screens on 8 March 2014. The Reunion discovery all-but-confirms the long-held belief that the aircraft turned south and crashed in the Indian Ocean.

Razak added that he hoped the discovery would “at least bring certainty to the families and loved ones” of those onboard MH370. “They have our deepest sympathy and prayers,” he said.

Malaysia Airlines issued a statement this morning, calling the discovery “a major breakthrough”.

“We expect and hope that there would be more objects to be found which would be able to help resolve this mystery.

“Moving forward, Malaysia Airlines’ priority will continue to provide latest updates and information to the families and will fully cooperate with the relevant authorities on the investigation and recovery of this tragic accident,” the airline added.