A police officer suffered burns after a boiling hot cup of coffee was thrown over him in a north London branch of Costa Coffee.
It happened in Mill Hill, and came just hours after two cops were attacked with a screwdriver less than a mile away.
Police were called to The Broadway, a busy high street, at about 11.30am on Thursday following reports of a bank card theft.
A short foot chase ensued and an officer had a cup of hot coffee thrown over him at the Costa shop.
A suspect was detained and arrested on suspicion of assault and theft.
The officer, meanwhile, had to be treated for burns by London Ambulance Service.
It came 18 hours after a man was arrested on suspicion of attempted murder in nearby Lawrence Gardens.
Two officers were attacked with a screwdriver, though their injuries were not life threatening.
