Mile 0, Jalan Tutong

Most people would know Kuala Belait is 67 miles from Bandar Seri Begawan. Where do they measure it from?I had a light argument with my editor - I am helping write some television scripts for a historical documentary series - and this topic came up. I said I clearly remembered when I was a little boy there was a mile 0 stone sign outside the Post Office where everything was measured from. Mile 0