Tim Blackman will meet Japanese prosecutors in Tokyo

Ms Blackman's body was discovered in a cave in February 2001, seven months after she went missing from Tokyo.

Tim Blackman, who comes from the Isle of Wight, spent tens of thousands of pounds on his own investigation into her disappearance.

Japanese property developer Joji Obara is standing trial accused of killing Miss Blackman, who was 21 and from Sevenoaks in Kent. He denies fatal assault, or rape resulting in death.

'Less satisfactory'

Mr Blackman will meet Japanese prosecutors and staff from the British Embassy when he arrives in Japan this weekend.

He said he was disappointed Mr Obara was facing only a manslaughter charge.

"From our point of view it's obviously a less satisfactory case than a murder charge," he said.

"We are in the hands of the Japanese authorities and that's the route they've gone down.

"The process is very meticulous, very thorough and very careful, which is why it's taken such a long time - they fully expect to have a positive result out of the trial."

The trial begins on Thursday.