Which countries have the biggest and most powerful militaries?

The UK has urged China to be open about its "biggest military build-up in peacetime".

Foreign secretary James Cleverly delivered a speech at Mansion House in London on Tuesday calling for China to be less secretive.

However, Cleverly stressed that isolating China would be a "betrayal" of the UK's national interest.

In a keynote address to the Lord Mayor's Easter Banquet, the foreign secretary warned: “At this moment, China is carrying out the biggest military build-up in peacetime history.

Watch: China displays military force towards Taiwan after US president's trip

“Secrecy can only increase the risk of tragic miscalculation."

But how does China's military compare with the largest foreign forces around the world?

Which country has the most active military personnel?

According to US data group the World Population Review, China has the highest number of active-duty military personnel, with more than two million members.

It is followed by India, which has almost 1.5 million, and the US, with just under 1.4 million.

North Korea isn't too far behind the US, with almost 1.3 million troops.

The only other country with more than one million active-duty military personnel is Russia, currently bogged down in its invasion of Ukraine.

The UK was in 34th place for active military personnel, with 148,500 troops.

Check out the interactive graphic below to see the full figures:

Which country has the most military aircraft?

When it comes to fighter jets and other military aircraft, China lags behind two countries – the US and Russia.

Citing data from Flight International magazine, World Population Review said the US has more than 13,000 aircraft in its military.

This includes more than 5,000 in the air force, more than 4,000 in the army, almost 2,500 in the navy and more than 1,000 in the marines.

Russia has more than 4,000 aircraft, predominantly in its air force.

China is in third place with more than 3,200 aircraft across its air force, army and navy.

Check out the interactive graphic below to see the full figures:

Which country has the highest military spending?

The three biggest national spenders make up more than 50% of the world's expenditure on the military, according to figures published this week.

Data released on Monday by the Stockholm International Peace Research Institute (SIPRI) showed that the US was the biggest military spender in 2022, with almost $900bn.

China was in second place, spending almost $300bn, with Russia in third, in the year it invaded Ukraine, with almost $90bn.

The UK was in sixth place, spending almost $70bn on military expenditure in 2022.

Which country has the most nuclear warheads?

As of early 2023, nine countries possessed about 12,500 nuclear warheads, according to the Federation of American Scientists (FAS).

It said that Russia and the US possess 89% of the world's total inventory of nuclear weapons.

Russia tops the list with 5,889 nuclear warheads, although 1,400 of those are retired, giving it a military stockpile of 4,489.

Of those, 1,674 are deployed in intercontinental missile and at bomber bases. The remaining 2,815 are classed as reserve or non-deployed, and are kept in storage.

The US has a military stockpile of 3,708 nuclear warheads, while China is in third place with 410.

The UK is in seventh position with a military stockpile of 105 weapons, according to FAS.

Watch: UK warns Russia of 'severe consequences' of nuclear use