Amateur film-makers sparked a full-scale police search involving officers from two forces and a helicopter, after passers-by reported seeing a body being dragged into Epping Forest under cover of darkness.

Vincent Tempest, 15, of Park Road, New Barnet, and Adam Young, 25, of Longfield Avenue, Mill Hill, were oblivious to the commotion after Adam carried a clothed blow-up alien wrapped in a bin bag into the forest while Vincent sat in a car with a camera on the evening of January 15.

The pair, who are members of Finchley Cinevideo Society, were making a movie for a competition about an actor who is killed.

Vincent said: "We dressed a big blow-up purple rubber alien in clothes and put a bin bag over its head. We dragged it across the road and Adam was dressed all in black with an undertaker's hat."

But several shocked passing motorists alerted police after they saw a body' in a bag and a shovel lying in the road. The occupant of one car sounded the horn and shouted: "Oi, let him go!"

Vincent said: "Police cars kept coming down the street, and when we saw about the fifth car, we realised they were probably looking for us."

The duo approached a police car and, within minutes, several other police vehicles arrived at the scene.

"We stepped out of the car and told them everything that happened," said Vincent. "There were three policemen searching the car with torches. One took the alien out and it made a squeaking sound. Then he took the bag off and revealed the purple head."

"He just stared at it and couldn't work out what was going on, and was looking up at the helicopter. He said: You do realise this is all because of you, the whole police force is out looking for a body.'"

"They understood and just said we should alert the police in future because Epping Forest is notorious for this kind of stuff."