LONDON (Reuters) - Britain may not have made a final decision on allowing China’s Huawei a restricted role in building parts of its 5G network, U.S. President Donald Trump’s national security adviser John Bolton said on Thursday.

FILE PHOTO: U.S. National Security Advisor John Bolton speaks during a graduation ceremony at the U.S. Coast Guard Academy in New London, Connecticut, U.S., May 22, 2019. REUTERS/Michelle McLoughlin

The Trump administration, which has sanctioned Huawei and tried to block it buying U.S. goods, has told allies not to use its 5G technology and equipment because of fears it would allow China to spy on sensitive communications and data.

Britain’s National Security Council, chaired by Prime Minister Theresa May, met to discuss Huawei last month and a decision was made to block Huawei from all core parts of the 5G network but to give it restricted access to non-core parts.

A final decision by the British cabinet of senior ministers was due to have happened in recent weeks but May’s pledge to step down as prime minister has stalled the process, sources said. She is expected to be out of office by the end of July.

When asked if the United States would like the next British leader to take a tougher stance on Huawei, Bolton said discussions with London were continuing but that Trump would probably raise it when he visits next week.

“I’m not sure that this decision has reached the prime ministerial level in final form. I mean we are still talking,” Bolton told reporters in London. “People are talking back and forth.”

“Everybody is catching up to the dangers posed, especially in 5th-generation telecommunications systems, by equipment from Huawei and potentially others that can allow foreign governments a back door into telecommunications systems,” he said.

5G, which will offer much faster data speeds and become the foundation stone of many industries and networks, is seen as one of the biggest innovations since the birth of the internet itself a generation ago.

In what some have compared to the Cold War arms race, the United States is worried 5G dominance would give a competitor such as China an advantage Washington is not ready to accept.

“WOBBLY”

Huawei, founded in 1987 by a former engineer in China’s People’s Liberation Army, denies it spies for Beijing, says it complies with the law and that the United States is trying to smear it because Western companies are falling behind.

U.S. Secretary of State Mike Pompeo told Britain on a visit this month that it needed to change its attitude towards China and Huawei, casting the world’s second largest economy as a threat to the West similar to that once posed by the Soviet Union.

“Now is not the time for either of us to go wobbly,” Pompeo said in a speech on the so-called special relationship, paraphrasing what former prime minister Margaret Thatcher once famously told late U.S. President George H.W. Bush.

Britain has said it will announce the findings of a review into 5G suppliers to parliament once the work has been completed, though May’s imminent departure from office has slowed the process.

Bolton said the issue of Huawei and 5G came down to a risk assessment but he repeated the fundamental view of the United States that the division between core and non core is less clear when it comes to 5G networks.

“5G really is not so easily divisible into core elements and peripheral elements,” Bolton said.

“How much risk are you prepared to accept that a foreign power is reading your mail all the time at their will?” Bolton asked. “When it comes to our government systems, the United States has said zero is the level of risk we will accept.”

The world’s leading intelligence-sharing network - the anglophone Five Eyes alliance of the United States, Britain, Australia, Canada and New Zealand - will not use technology from Huawei in its most sensitive networks.

For Britain’s spy masters, the riddle of Huawei is only a part of the wider challenge of securing 5G networks and what they see as the much more fundamental threat from China’s dominance in certain globalized technologies of the future.