Charlotte Walker drowned when the car in which she was travelling plunged into the water at Sixteen Foot Bank, Stonea, on February 20.

The inquest at Wisbech on Friday heard passing motorists waded into the freezing water in a desperate attempt to save Charlotte.

But, with the Citroen Picasso sinking fast and Charlotte unable to escape, there was nothing they could do.

Charlotte’s mother Lynn, who had managed to free herself from the car, watched helplessly from a bank.

Eyewitnesses said the car driven by Mrs Walker, of Tipps End, Welney, went out of control moments before it plunged into the drain.

Motorist Jayne Webb said the Citroen was “swerving” as it approached her on the opposite side of the road.

She said: “My daughter was sitting beside me and I said ‘oh my God, what is that car doing’? My daughter said ‘she is going to hit a telegraph pole’. It’s just seconds isn’t it? Then there was a shower of stones and dirt. I shut my eyes and when I opened them again and looked, I could see the car going into the water.”

Another eyewitness Jon Jones said: “The woman (Mrs Walker) was shouting that her daughter was still in the vehicle.”

He said that the Citroen was soon “completely submerged” and the water was “extremely cold”.

PC Stephen Edwards said Charlotte, a former pupil at Townley Primary School, Christchurch, was in the rear of the car.

She had managed to take off her seatbelt but could not escape from the car.

Mrs Walker only spoke to confirm her name and that she was the driver of the Citroen which had been carrying Charlotte.

Recording a verdict of accidental death, deputy coroner David Osborne said it appeared that Mrs Walker “lost control” of her vehicle before it plunged into the drain.

A statement released by the family following the inquest said: “Charlotte was a wonderful child who touched many people’s lives and she will be greatly missed by us all. Now is a difficult time for us and we would appreciate a private time to allow us to grieve.”