It is doubtful that night vision goggles would have helped avoid a mid-air crash between two helicopters at the start of the Iraq war in 2003, an inquest in Oxford has been told.

Seven men from RNAS Culdrose died when their Royal Navy Sea King helicopters collided near the aircraft carrier HMS Ark Royal.

The inquest has been told there was no need for night goggles which did not turn night into day On the day of the crash visibility was down to two nautical miles. Both aircraft were in good working order.

The inquest has heard that the pilots told air controllers they had seen each other minutes before the crash.

The recording of radio messages giving the vital sighting in time was lost in the explosion.

Investigators have found no evidence to suggest a mechanical fault caused the crash.

The men who died were all from 849 Squadron based at RNAS Culdrose.

Lt Philip Green, 30, from Caythorpe, Lincolnshire; Lt King, 35, from Helston; Lt Marc Lawrence, 26, from Westgate-on-Sea, Kent; Lt Philip West, 32, from Budock Water; Lt James Williams, 28, from Falmouth; and Lt Andrew Wilson, 36, from Exeter, Devon, died alongside a US serviceman.

One aircraft piloted by Lt Wilson, had been returning from a sortie. The second helicopter was piloted by Lt Green and was due to continue the sortie.

But it was delayed by a fault with its communications equipment and took off minutes before the other returned.

The inquest continues.