1999: The T2K experiment was first proposed by Koichiro Nishikawa and Yoji Totsuka in order to search for oscillations from muon neutrinos to electron neutrinos.
2001: A formal application for funding for the project was made by submitting a Letter of Intent.
2001: Start of construction of the proton accelerator at the Japan Proton Accelerator Research Complex (J-PARC) in Tokai.
2002: The T2K collaboration first formed, though it was smaller than the current collaboration and had a different name.
2003: The T2K project was officially approved by the Ministry of Education, Sports, Culture, Science and Technology in Japan.
2006: The T2K collaboration expanded, and was launched using the name “T2K”.
2006: Submission of T2K experiment proposal
2007 – 2009: Construction of the ND280 near detector (the SuperK far detector had been used by previous experiments since 1996).
2008: SuperK detector electronics upgraded in preparation for T2K
2009: First neutrino beam produced by the proton accelerator at J-PARC.
2010: First physics data taken in the ND280 near detector and the SuperK far detector.
You can contact the current T2K spokespersons here.