Poland and the US have signed a memorandum that may pave the way to Warsaw buying Patriot surface-to-air missile interception systems from US company Raytheon, the Polish defence ministry said on July 6 with the Donald Trump visit to the Polish capital under way.

Poland has long planned to buy Patriot batteries as part of a plan to boost defence. Warsaw wants to upgrade its armed forces' deterrence and defence potential as tensions continue to spook Central and Eastern Europe. Poland and the Baltics have become highly sensitive to any threatening Russian foreign policy since Moscow’s takeover of the Crimea peninsula from Ukraine in 2014.

The “memorandum of intent” signed by the Polish defence ministry and the US department of defence says the US will deliver a buy offer to Poland by December. If the contract is eventually agreed, Patriot batteries are expected to achieve “initial operational capability” in 2023, the memorandum said.

The memorandum is not binding, although it appears a genuine step forward in closing the Patriot purchase, given the timing of its announcement. US President Trump's visit to Poland on July 5-6 is dealing with issues including security and energy cooperation.

The agreement is important because of “the adversary standing opposite us and the [Russian] Iskander missiles that threaten Poland that can be effectively countered by the Patriot missiles,” Polish defence minister Antoni Macierewicz said. He added that Poland will receive the "latest configuration" of the system.

The proposed Raytheon deal, valued at about PLN30bn (€7.1bn), has gone through a number of twists and turns. In late 2015, Macierewicz suggested the deal would not be done, but he eventually backtracked to allow the talks to progress.

Poland’s drive to overhaul its armed forces has not been without controversy. A deal with France’s Airbus to supply helicopters for PLN8bn-12bn collapsed last year, provoking a diplomatic spat with Paris. Poland is now reviewing offers from Airbus and other producers again, but the scope of the helicopter order has been reduced, while the timing remains unclear.