BANGKOK (Reuters) - Thai protest leaders said on Friday they expected the biggest anti-government demonstration in years this weekend and vowed to reiterate their calls for reforms of the monarchy despite official pressure to stop. Demonstrators have since mid-July been demanding the removal of Prime Minister Prayuth Chan-ocha, a former junta leader, and changes to a constitution they say was designed to extend military domination of politics after a general election last year. Some protesters have also called for unprecedented reforms of the monarchy, previously a taboo subject in Thailand. “Tomorrow’s rally will make history and will be the biggest one since the 2014 coup,” Parit “Penguin” Chiwarak, one of the protest leaders, told Reuters, adding that he believed as many as 100,000 people could show up. Police said they expected up to 50,000 to join the protest. Thai politics has for years been marked by challenges to the royalist, military establishment by politicians backed by poor urban and rural voters, and more recently by the student protesters. The military, which proclaims itself the defender of the country’s core institutions, in particular the monarchy, has stepped in to overthrow civilian governments numerous times, most recently in 2014, citing the need to maintain stability. Tens of thousands of protesters are due to gather on Saturday at Bangkok’s Thammasat University and march to the prime minister’s offices, known as Government House, on Sunday to put pressure on Prayuth. A group of protesters from the university last month staged a rally at which a 10-point demand for reform of the monarchy was read out, including a call for the abolition of a law against royal criticism. Prayuth has said the government would allow protests as a form of free speech, but that demands for reform of the monarchy were not acceptable. Parit said the demands would be reiterated this weekend. Thammasat University said last week it would not allow the gathering on its campus, but protesters said they were sticking to their plan. They will also use nearby Sanam Luang, a large open space in front of the Grand Palace. Police said marching to Government House could break a law prohibiting large gatherings near restricted sites. On Thursday, Prayuth warned the protesters against raising the risks of spreading the novel coronavirus and urged them to put the health crisis before politics.