The Special Cell of Delhi Police has registered an FIR in connection with the protest staged by pro-Khalistani activists at the Indian High Commission in London on March 19 during which the Tricolour was pulled down from the premises.
According to a senior police official, the case was registered after the Union Ministry of Home Affairs asked Delhi Police to take legal action.
"The FIR was registered under relevant sections of Indian Penal Code, Unlawful Activities (Prevention) Act and Prevention of Damage to Public Property Act and an investigation has been initiated in the matter," said the official.
On Sunday, the British Deputy High Commissioner was summoned by the Centre, demanding an explanation over the complete absence of security during the protest.
The British High Commissioner to India Alex Ellis described the incident as "disgraceful" and "totally unacceptable".