The Government will do “whatever it takes” to keep the UK safe from the threat of spy balloons, Rishi Sunak has said.

It come after Defence Secretary Ben Wallace announced Britain will conduct a security review after a series of objects in western airspace was shot down by the US military, including a suspected Chinese spy balloon.

The Prime Minister said that “national security matters” prevented him from commenting in more detail, but insisted that the UK was in “constant touch” with allies.

US fighter jets shot down an “unidentified object” over Lake Huron on Sunday – the fourth object to enter US or Canadian airspace in just over a week.

On February 4, the US military downed a suspected Chinese spy balloon off the Carolina coast after it travelled over sensitive military sites across North America.

Almost a week later on Friday, they shot down an unknown “car-sized” object flying in US airspace off the coast of Alaska.

Canadian Prime Minister Justin Trudeau said on Saturday that he ordered a US warplane to shoot down an unidentified object that was flying high over northern Canada.

On Sunday, a further unidentified object was shot down with a missile by US fighter jets over Lake Huron.

“I want people to know that we will do whatever it takes to keep the country safe,” Mr Sunak told broadcasters during a visit to Royton, Oldham.

“We have something called the quick reaction alert force which involves Typhoon planes, which are kept on 24/7 readiness to police our airspace, which is incredibly important.

“I can’t obviously comment in detail on national security matters, but we are in constant touch with our allies and, as I said, we will do whatever it takes to keep the country safe.”

The Prime Minister declined to be drawn on the possibility of similar incidents in UK airspace.

“People should be reassured that we have all the capabilities in place to keep the country safe,” he said.

Transport minister Richard Holden earlier suggested that it was “possible” that Chinese spy balloons might already have been been used over the UK.

“It is also possible, and I would think likely, that there would be people from the Chinese government trying to act as a hostile state,” he told Sky News.

Mr Holden said the UK had to be “robust” in how it dealt with Beijing, admitting the UK Government was “concerned about what’s going on” in the US.

The former chief of MI6 said China’s potential use of spy balloons was “not a good look” but that the cyber threat posed by Beijing is greater.

Sir Alex Younger told Times Radio: “I question that this is particularly significant in the context of all the other collection that will be taking place. It’s visible.

“The thing that we have all been focused on for years is the cyber threat. The threat that comes from the sort of internet and other cyber connectivity. And that, I think, is normally underestimated because you can’t see it.

“This is something that’s literally visible, and therefore seems to attract a completely different reaction.”

Asked whether balloons were an embarrassment as a strategic weapon, he said: “It’s not a good look. They’re presenting themselves to the non-aligned world as guardians of the sovereignty of developing nations, and this just is a very different message.”

Downing Street said that the UK was “well prepared” to deal with security threats to British airspace, with threats judged on a “case-by-case” basis.

The Prime Minister’s official spokesman did not use Mr Holden’s word “hostile” to describe China, but indicated that the foreign policy designation of the country will be reviewed as part of the update to the integrated review of security, defence, development and foreign policy.

“China poses a systemic challenge to our values and interests.

“It is a challenge that grows more acute as it moves to even greater authoritarianism.

“You will know we are updating the Integrated Review and it will take into account some of these evolving challenges we are seeing,” the spokesman said.

Mr Wallace said on Sunday that the UK and its allies would “review what these airspace intrusions mean for our security”.

“This development is another sign of how the global threat picture is changing for the worse,” the Defence Secretary said.

Tobias Ellwood, the Conservative chairman of the Commons Defence Select Committee, said China was “exploiting the West’s weakness” with the potential spy balloons.

The former defence minister told Times Radio: “I think this is a testament as to where China is going.

“It is interpreting our wobbly international rules-based order to its own benefit.”