"And the cost sseem similar or higher than a P-8"
Japanese MOD press conference on P1 funding for SDF below.
P1 Cost around 95 million GBP each. (Fag packet sums- happy to be corrected)
Extra Press Conference by the Defense Minister Nakatani(02:43-02:50 P.M. January 11, 2015)
"
Minister:
I held a negotiation with the minister of finance a short while ago, in which he approved our plan to procure 20 P-1 fixed-wing patrol aircraft through a long-term contract. In addition, the finance minister also approved our plan to appropriate 350.4 billion yen for that purpose. We had requested that amount to deal with security issues in sea areas surrounding Japan including the southwestern region.
This approval is extremely vital for us from the viewpoint of improving the Self-Defense Forces operations and strengthening Japan's defense capability. With the enhancement, we intend to firmly protect Japan's maritime security.