The Indian Government has approved an agreement with Boeing to buy eight P-8I long-range maritime patrol aircraft for the Indian Navy in what will be the largest-ever defence deal between the US and the sub-continent.

The aircraft will be used for long-range maritime reconnaissance and anti-submarine warfare and will replace the Indian Navy’s ageing Tupolev Tu-142M maritime surveillance turboprops.

The aircraft, a derivative of the Next-Generation 737-800, can reach a maximum speed of 490 knots (789kmph) and can fly a range of more than 1,200 nautical miles, with four hours on station.

The aircraft is powered by two CFM56-7 engines, which provide 27,300 pounds thrust each.

The Indian Navy will be the first international customer to receive the P-8I.

Under the $2.1bn deal. Boeing will deliver the first P-8I patrol aircraft by 2013 and the remaining seven by 2015.