Ex-NATO chief says UK may get 'frosty' Ankara welcome in absence of 3.5% plan

LONDON, July 7 (Reuters) - Former NATO chief and co-author of Britain's defence plan, George Robertson, criticised the government on Tuesday for not plotting a route to spending 3.5% on core defence and predicted a "frosty" response from NATO allies at a summit this week.

Robertson, a Labour grandee who helped draft Britain's Strategic Defence Review last year, stepped up his criticism of Prime Minister Keir Starmer's defence spending plans, which included an extra £15 billion ($20 billion) to modernise the depleted armed forces and prepare for the wars of the future.

That target of spending 3.5% of gross domestic product on core defence and an extra 1.5% on broader national security by 2035 was set by NATO allies last year to respond to U.S. President Donald Trump's demand for European nations to spend and do more to defend themselves.

As Starmer headed to Ankara for the NATO summit, Robertson said Britain was "running out of years" to prepare for what he described as threats to the alliance that clearly have now been accelerated from when he helped write the defence review.

"Quite simply we are running out of years and the reality is that the challenge is now bigger, more serious and earlier than we had anticipated and yet the Defence Investment Plan itself does not come up to it," he told a parliamentary committee.

Robertson, who served in the 1990s as Britain's defence minister before leading NATO, said the months-long delay in publishing the Defence Investment Plan had not only deterred investment, it had also angered allies with "its inability to project forward the commitment to the 3.5%".

The criticism at home and any similar pronouncements at the NATO summit could overshadow what is Starmer's last foreign trip before he is expected to hand over power to former Greater Manchester mayor Andy Burnham, as soon as July 20.

Robertson said when Starmer sits down next to Trump and other NATO allies at the summit on Wednesday: "I think relations may well be frosty."

($1 = 0.7479 pounds)

(Reporting by Elizabeth PiperEditing by Tomasz Janowski)