Poland signed a deal on March 28 to buy a Patriot missile defence system from US manufacturer Raytheon for €4.75bn (€3.85bn). The deal – the largest in the country’s history – will bolster the capability of the largest Nato member in Eastern Europe to respond to an attack, as Warsaw is increasingly wary of Russia’s geopolitical ambitions regaining vigour.

Poland is one of only a few Nato member states that spend the alliance-recommended 2% of GDP on defence. Following Russia’s unlawful annexation of Crimea from Ukraine in 2014, Warsaw has stepped up efforts to modernise its armed forces.

Raytheon will deliver two Patriot batteries together with the command system known as IBCS by the end of 2022; the new defence equipment will achieve the so-called “initial operational capability” at the turn of 2023 and 2024, Poland’s defence ministry said.

The deal comes with an offset agreement – which is carrying out part of the work under the deal in Poland to give business and create jobs for the domestic defence industry – that is worth PLN950mn (€226mn).

“It is a unique and historic moment that ushers Poland into a new world of ultra-modern technology and weaponry,” Poland's President Andrzej Duda said upon the signing of the deal.

Poland’s defence ministry said its negotiating team managed to bring down the price from the initial offer of $10.5bn.

"This is a lot of money but we know that security has no price,” Duda said referring to the final price.

The deal marks the kick off of a key element in the first phase of Poland’s air and missile defence programme Wisla.

Warsaw plans to further boost its defence capability in the second phase of the programme, the terms of which it will promptly start negotiating with Raytheon, the defence ministry said.

Poland wants six additional Patriot batteries in the second phase, as well as 360-degree radars, and an interceptor missile, Raytheon said in a statement.

The deal should ease tension between Poland the US that rose recently, following Poland’s passing of the controversial “Holocaust speech” law that makes it a criminal offence to suggest Poland or Poles were complicit in Nazi atrocities during the Second World War.

The deal is the current Law and Justice (PiS) government's first major arms deal since taking office in 2015. Earlier, PiS scrapped a multi-billion euro deal with France’s Airbus to buy helicopters for the Polish army, sparking a diplomatic row with Paris.