PM Pedro Sánchez says he wants a ‘more flexible formula’ that would make target optional or allow Madrid to opt out

Spain’s prime minister, Pedro Sánchez, has rejected Nato’s proposal for member states to increase their defence spending to 5% of their GDP, saying the idea would “not only be unreasonable but also counterproductive”.

Sánchez said that he was not seeking to complicate next week’s Nato summit in The Hague, but he wanted there to be a “more flexible formula” that would either make the target optional or allow Spain to opt out.

The proposal – advanced by the Nato secretary general, Mark Rutte, in response to Donald Trump’s demands for a 5% target – suggests member states agree to raise defence spending to 3.5% of their GDP and commit a further 1.5% to wider security spending.

In a letter to Rutte that emerged on Thursday, Sánchez questioned the possible consequences of such a rise, saying it would be incompatible with Spain’s welfare state and its vision of the world.