A passenger jet was forced to make an emergency landing after a mysterious mid-air collision with a ‘foreign object’ at 26,000ft severely dented its nose cone.

The front of the Air China Boeing 757 had been pushed in and scratches and scraped paintwork  were clearly visible when it landed.

The plane was climbing over China when a large bang was heard from the front of aircraft.

The pilot said the aircraft was struggling to perform and he immediately called air traffic controllers, according to reports.

Experts said investigations into the suspected crash have raised suspicions that the aircraft was hit by a ‘foreign object’.

However, they do not believe it was caused by a bird strike as no blood or feathers were visible on the dented nose cone.

The pictures have prompted online speculation that it was caused by a UFO or a drone strike.

Other theories posted on the Aviation Herald include pressure from rapidly heated and expanded air.

Former government UFO investigator Nick Pope told The Sun that an examination of the nose cone should reveal what hit it.

However, he questioned whether the ‘secretive’ Chinese would reveal the cause.

Mr Pope told The Sun: ‘Cases like this show that whatever people believe about UFOs, there are serious air safety issues here.