A British teacher died in Thailand after she was swept over a water fall.

Thirty-year-old Sarah Crutchley lost her footing while walking across the top of the Ton Nga Chang falls, The Sun reported.

Though she was able to hold on to a boulder for a few seconds, the strong torrent washed her away.

'I tried to get to her but I also slid and fell, and grabbed another rock...the current was just too strong for her and she lost her grip,' Sarah's friend Chris Penny was quoted as saying.

'She slid about ten metres down a rocky slope and then fell over the edge. It must have been a 100-metre drop. It was just horrible to watch.'