A BRAVE 999 caller has spoken out about his desperate attempts to raise the alarm after witnessing a man 'going under' in the River Thames this morning.

The gentleman, who lives in Caversham and asked to remain anonymous, quickly phoned the police at 10.05am when he spotted a man in the water next to Reading University Boat Club, near Caversham Bridge.

A search and rescue operation is currently still underway to find the missing man, described as Asian and in his 30s.

Speaking exclusively to The Chronicle: "I was doing my usual walk when I saw a man in the water. I phoned 999 but he had already gone under.

READ MORE: Emergency services searching for man in the River Thames in Caversham - live

"It didn't look like he was struggling. He was either in shock or didn't know how to swim. At first, I thought it was one of those wild open water swimmers you see in lakes but at 10 o'clock on a Monday morning is random, then I realised his head and arm were slowly going under."

The man said he helplessly tried to save the man, calling for two kayakers in the water to help.

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He said: "Me and one other woman were simultaneously shouting at the two chaps kayaking. They just disappeared but could have done something. I could swear I heard the man say 'help' but it might just be me."

The witness also felt "frustrated" that there were was not "one single lifebuoy" he could have used to help save the man.

He added: "I've sent an email to the council about the lack of life-saving rings along the river, just because some ars****** have decided to vandalise them on this key piece of infrastructure. I do feel frustrated there wasn't one there. I walk on Caversham bridge every single day."

The caller praised emergency services for arriving within "five minutes" of his call.

t the time of writing, the fire and rescue service had withdrawn from searching the Thames with Thames Valley Police expected to take over.

Anyone with information is asked to contact police on 101, quoting incident 438 of 10 January