Three people were seriously injured after a policeman who was allegedly drunk crashed his car into a roadside restaurant in Bangkok on Monday.

Shocking CCTV footage shows the black sedan mowing down customers at the Chinese barbecue shop in the Saphan Mai area of Bangkok on February 6.

Three people were sent to intensive care after the crash, while the driver, Ekapong Ariyadip, was detained.

He claimed that he had swerved to avoid a car making a U-turn, causing him to lose control.

The restaurant's owner said he feared that the suspect might evade punishment as he is a police officer.

However, Police Lieutenant Colonel Sarawut Butdee, deputy superintendent of the Bang Khen police, said: 'We would like to reassure everyone that the prosecution will be fair.'

A test revealed that Police Major Ekapong's alcohol levels during the accident were at 126 milligrams, which is above the allowed threshold.

He was charged with driving under the influence of alcohol, reckless driving resulting in serious injury, and reckless driving resulting in damage to property.

Officers said they are gathering evidence and witness statements as the investigation continues.