An inquest into his death heard he suddenly grabbed the woman as he swam with her towards the deep end before going under the water.
The woman, referred to in court only by the name of Rachael, said that at first she thought it was just horseplay and she wriggled free.
The court heard there was some doubt as to whether Mr Echukwu - a Nigerian-born social worker from Edgware, Middlesex, could swim or not.
Rachael - who obtained a High Court Order this week stopping any information appearing which might lead to her identification - told the inquest: "I don't think I even knew his name. I don't remember it. He was really polite. He didn't talk on the dance floor and I don't remember him being drunk.













