UPDATE: Man fights for life after speedboat crash near Southampton

• Speedboat crash near Southampton - in pictures >>

The victim, believed to be in his late teens, is being treated for life-threatening injuries at Southampton General Hospital.

Three other men were injured in when the speedboat flipped over and capsised at the entrance of Hamble Point Marina.

Two are aged in their 50s and another in his 20s.

A coastguard rescue helicopter was sent to the scene just after 8.30am.

Police and the Marine Accident Investigation team have both launched probes into how the crash happened.

The incident, witnessed by many horrified onlookers, happened in water close to the Warsash Maritime academy, which is on the River Hamble close to the entrance to Southampton Water, at around 8.20am this morning.

The Maritime Coastguard Agency said it had received multiple 999 calls to the incident and four people were on board and three are injured and another one seriously injured.

It added one person was taken ashore by lifeboat and taken to Southampton General Hospital by ambulance.

Two lifeboat crews from Calshot are at the scene along with an ambulance, the police marine unit and a helicopter from Lee-on-Solent.

Gary Pullen (pictured above) was running on shingle coastline near Solent Breezes campsite, Warsash, when he saw the speedboat roar past.

He said: "I had my headphones in but the boat was so loud you could hear it over the top of the music.

"It was going up and down the waterway and came back around. It looked like it was going to turn around the buoy and it flipped over. IT was difficult to tell if it hit it or not. I heard the engine but don't recall a splash."

Gary, 33, a dad of two, immediately called 999 asking for the coastguard added: "the adrenaline kicked in. I was in shock because I thought to myself there was going to be an accident and it just happened."

After a couple of minutes he saw movement in the water and saw a figure and added: "they were waving and I was waving back.

"I said to the operator I wanted to get in and help but they said it was too dangerous."

A fishing boat arrived first before coastguard and RNLI crews.

In the commotion Gary did not see the people rescued.

But he added: "I just hope and pray they make a recovery."

Frenchman Daniel Ubertini, 66, from Hamble, said he had been watching the boat, which he said was travelling “very fast”, he estimated 15 knots or more, when he saw it flip landing on a large yellow buoy close to the entrance of Hamble Point Marina.

“I heard the boat going to Southampton at very high speed, it changed speed to go faster so I took some pictures and then the boat went back to Gosport,” said Daniel, who is working on a yacht at Hamble Point Marina.

“Then when he went back from Gosport I heard the noise of the engine. I started to shoot the boat.

“I didn’t see when I shot the picture that he was in the air hitting the buoy.

“After that there was no more noise, the boat was upside down and the cabin was inside the water.

“I didn’t see anyone.”

He said the boat had been towed into Hamble Point Marina by the Harbour Master.

Garry Ames, 42, of Swanwick, also at Hamble Point Marina, said he believed the boat was a Vector Martini race boat that is normally moored at Driver's Wharf on the River Itchen and that he has seen out on the water many times.

He said the helicopter has now landed in a field close to the Rising Sun pub in Warsash and there were now five ambulances and other rescue services on scene.

Ernie Ackland driver of Hamble ferry said: "It was quite dramatic but quite often you see things like this here. It was a pretty well oiled operation."

The ambualnce service sent a hazardous area response team, the Thames Valley Air Ambulance, four ambulances and an ambulance officer.

All were treated at the scene and then taken to hospital.