“We’re no longer humans behind bars,” said Mr Nyi Nyi Htwe, 24, who smuggled the sketches out of the prison when he was released in October, after spending several months for a defamation conviction, on charges he denies, in connection with joining protests against the coup.

According to the latest figures from the nonprofit Assistance Association for Political Prisoners (AAPP), the junta has killed 1,733 and jailed 13,132 of its opponents since it overthrew the democratically elected government in February 2021. 

Insein, built by the British in 1871, and intended to incarcerate some 5,000, has seen its inmate numbers to swell to over 10,000 since the coup, said an AAPP spokesperson. The sketches by the anonymous artist between April and July of last year reflect that overcrowding. 

Mr Nyi Nyi Htwe said he and as many as 100 others were packed well beyond capacity into a room where they “slept a finger-width apart”, and that he watched prison officers beat inmates with batons and had to pay bribes to send messages to family that they told him often did not arrive.