SEVEN people have been killed after a plane crashed into cars on a major road during an aerial display at the Shoreham Airshow.

The Hawker Hunter crashed just north of Shoreham airport at about 1.20pm.

A further 15 people have been injured, with one in a critical condition at the Royal Sussex County Hospital.

The others were being treated at the scene, the ambulance service said.

The condition of the pilot is not yet known.

The A27 was closed in both directions between Lancing and north of Hove, and Blackburn Rovers' game at Brighton was delayed by 15 minutes.

Witnesses described a "huge explosion" as the plane hit the ground. 

 Jason Gunn, 53, said: "I was watching the display standing on top of my car.

"As it came down, it seemed like it didn't have enough power to lift it up.

"I saw it just going below the tree and I expected it to come up.

"But it didn't and suddenly - boom boom.

"It looked as if it split in half."

Nigel Dennis, from Hurstpierpoint, was among witnesses who said the plane appeared to be flying too low before it crashed.

He said: "They announced the Hunter. It swooped in, it turned around as it was coming down flat to go up but he went down too low.

"Then just woof, flames and smoke."

An Air Accidents Investigation Branch (AAIB) spokesman said it was aware of the incident and would investigate.

Organisers have cancelled tomorrow's show.

Tim Loughton, MP for East Worthing and Shoreham, said his thoughts were with those affected.

He said: "It's tragic news that it has been confirmed that there have been fatalities and we obviously hope that those numbers will not increase.

"Given the many thousands of people attending the air show we thank God that the aircraft did not hit a larger crowd."

Mr Loughton drove past the entrance to the air show a few minutes before the crash.

He said: "There was about a couple of hundred yards of cars queueing at the entrance to get in as well as stewards and some spectators sitting by the roadside.

"It's horrific. It is a horrendous crash."

Footage of the crash posted online showed the jet carrying out a loop manoeuvre high in the air but failing to pull up in time.

There appeared to be queueing traffic on the A27, and then the plane slammed into the ground and burst into a ball of flame and smoke. The pilot did not appear to deploy the ejection system.

Photographs taken by witnesses showed the burning aircraft ploughing across the road just yards from cars and a group of people, its canopy open and wing ablaze, engulfing traffic lights and roadwork cones and signs in a huge ball of fire.

Prime Minister David Cameron sent his "heartfelt condolences" to the families of those who died in the crash.

A Downing Street spokesman said: "The Prime Minister sends his heartfelt condolences to the families of the people who were so tragically killed after a jet crashed into several vehicles in West Sussex.

"The Prime Minister's thoughts and prayers are with the families and friends of the victims."

It is the second fatal incident at the Shoreham Airshow in recent years.

In September 2007 James Bond stuntman Brian Brown, 49, died when he crashed a Second World War Hurricane after carrying out an unplanned barrel roll at a re-enactment of the Battle of Britain.