A man from Sutton drowned after a friend pushed him from a yacht in "prank gone wrong" during a stag party in Portugal.

The body of Nishanthan Gnanathas, 32, of Selwood Road, was found in the Tagus river in Lisbon on Friday, six days after he went overboard.

The City worker, of Selwood Road, is thought to have struck his head as he tussled with a friend on Saturday, July 16, while celebrating a pal’s upcoming wedding.

Investigators said he was “unconscious and without a life jacket” when he plunged into the river.

The financier, an Imperial College London graduate who worked for Millennium Partners, was part of a group of 12 friends on board the boat when he fell, sparking a sea and air search involving about 30 rescuers.

Maritime Police chief Malaquais Dominguez, who took witness statements from friends of Mr Gnanathas following his disappearance, told the Sutton Guardian today he believed his death was a tragic accident.

He said: “I am satisfied that it was a stupid joke between friends. He was pushed and he went overboard. He disappeared in the water.

“My divers were out for hours after but he was not in the area.

“I was with my team when the body was found. He was found around two kilometres from where he disappeared.

“I myself called the father and, obviously, he was very concerned.”

The unnamed man who allegedly pushed Mr Gnanathas from the boat was officially made a ‘person of interest’ by Portuguese police after witnesses identified him as the person who took part in the prank, according to Mr Dominguez.

But the police chief said: “The court will rule if there will be any further investigation, I cannot tell you that that will be the case at this point."

However, it is understood that Mr Gnanathas's family have been told no charges will be filed against his friend as he is not thought to have intended him any harm.

A neighbour of Mr Gnanathas’s family said this week: “They must be broken. I mean I feel broken and I don’t even know him that well.

“I cannot imagine what they are going through. They are such a lovely family and it is horrible that things like this have to happen.”

A spokeswoman for the UK Foreign Office said: "We are providing consular support to the family of a British national who sadly died in Portugal.

"We remain in contact with local authorities."