London's landmark Walkie Talkie building has been sold to a Hong Kong group best known for making oyster sauce in the UK's biggest deal for a single office building.

The building at 20 Fenchurch Street has been bought by Lee Kum Kee, a food business best known for its oyster and soy sauces, for £1.3bn.

The skyscraper becomes the latest trophy building in London to be snapped up by foreign investors.

The deal beats the £1.15bn sale of the Cheesegrater skyscraper in Leadenhall to Chinese investors earlier this year, and the £1.1bn paid by Qataris for the HSBC Tower in 2014.

British property group Land Securities, which owned 50% of the building, said it had exchanged contracts with LKK Health Products Group Limited – a division of the broader Lee Kum Kee Group – which would also buy the remaining 50 % stake controlled by Canary Wharf Group.

The 37-storey Walkie Talkie building at the heart of the City boasts around 700,000 square feet of office space, 17,000 feet of retail space and also the Sky Garden tourist attraction.

Land Securities chief executive Robert Noel said: "This sale crystallises the significant value we have created at 20 Fenchurch Street."

The Hong Kong group said the acquisition was a "long-term investment" that extends its property portfolio and will provide a "reasonable return" from rental income.

Lee Kum Kee was founded in 1888 when Lee Kum Sheung invented his own variety of oyster sauce in the Guangdong Province of China. The firm now makes over 200 sauces and condiments which it sells in over 100 countries.