LONDON - British Prime Minister Rishi Sunak and his Japanese counterpart Fumio Kishida will sign a defence agreement in London on Wednesday that will allow the countries to deploy forces on each other's soil, the latest move towards closer security ties.

Kishida and Sunak will sign the reciprocal access defence agreement, agreed in principle last May, a month after the two countries teamed up with Italy on a new fighter jet programme.

The visit and agreement form part of Britain's Indo-Pacific tilt in foreign policy strategy as it builds security and trade ties in the region.

"This Reciprocal Access Agreement is hugely significant for both our nations - it cements our commitment to the Indo-Pacific," Sunak said in a statement.

"In this increasingly competitive world, it is more important than ever that democratic societies continue to stand shoulder to shoulder as we navigate the unprecedented global challenges of our time."

Kishida is visiting Britain as part of a tour of Group of Seven (G7) countries including France, Italy, Canada and the United States. Japan currently holds the G7 presidency.

Downing Street said Sunak would raise the need for the group to maintain its collective support for Ukraine as the first anniversary of Russia's invasion approaches in February.

Underpinning the desire for closer ties, Britain and Japan have also both described China as a challenge in the Indo-Pacific region.

Chinese foreign ministry spokesperson Wang Wenbin said that the region was "not an arena for geopolitical games" and China was a partner for co-operation and "not a challenge".

"The old thinking of bloc confrontation should not be introduced into the Asia-Pacific region," Wang told a briefing in Beijing when asked about Japan and Britain's pact.

Sunak and Kishida are also expected to discuss trade and Britain's accession to the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP). In December Britain and Japan also launched a digital partnership.

Sunak will meet Kishida at the Tower of London, a medieval fortress and one-time prison which houses the Crown Jewels and other treasures. The leaders will see some Japanese armour, which was presented to King James in 1613 by Shogun Tokugawa to mark the first trade agreement between England and Japan.

(Reporting by Alistair Smout, additional reporting by Liz Lee; Editing by David Gregorio and Tomasz Janowski)