More than 100 firefighters are battling a blaze at Somerset House in central London.
Twenty fire engines and about 125 firefighters were at the scene, the London Fire Brigade said.
“Crews are tackling flames located in part of the building’s roof,” the fire brigade said.
“Two of the Brigade’s 32m ladders have been sent to the scene to support firefighting operations.
“The entire site at Somerset House is now closed to the public whilst we tackle the fire.
“Traffic in the surrounding area will be impacted as crews respond.”
The first call about the fire was received at 11.59am on Saturday (9pm AEST).
The number of crews continues to rise – initially the fire brigade said it was 10 fire engines and 70 firefighters before it was increased to 15 fire engines and almost 100 firefighters.
The latest figures came about 2.30pm (11.30pm AEST).
Somerset House said all staff and members of the public who are at the venue are safe.
Somerset House is an iconic building on the Strand, near to the Australian High Commission, and at its southern end overlooks the River Thames.
The complex was first built in the 1500s, though it was demolished and rebuilt in the 1700s.
The future Queen Elizabeth I lived at Somerset House until 1558.
In 1604, the Treaty of London was signed within the building, ending the 19-year Anglo-Spanish War.
Somerset House is now the host of creative events and exhibitions. On Saturday, it said a dance battle was supposed to be held in the building’s open air courtyard, with “a day of dance and breaking showcases, workshops, live DJs and a big outdoor party, all culminating in a head-to-head dance battle between the four corners of London”.
