Julian Assange’s fight against extradition to the US could last years, and his argument could hinge on reports he has been illegally spied upon and his sensitive information given to the CIA.

Meanwhile, more than 100 doctors from across the world have written to the Australian government, urging it to act and “protect the life of its citizen”, in a letter to be delivered to the foreign affairs minister on Tuesday, amid warnings Assange’s health continues to deteriorate.