Pro-democracy protesters in Thailand have rallied again, promoting a diverse range of causes and taking an opportunity to display their rejection of the country’s power structure directly to the monarch.

Some 20 groups called the rally at Bangkok’s Democracy Monument under the name “Mob Fest” as the latest in a series of protests calling for significant reforms in government.

The core demands of the main student-led protest movement are that prime minister Prayuth Chan-ocha step down, the constitution be amended to make it more democratic, and the monarchy be reformed to be made more accountable.

The demand over the monarchy is the most controversial because the royal institution is traditionally regarded as the heart and soul of the nation, and to be treated with the utmost respect.

It is protected by a law that makes defaming the monarch punishable by up to 15 years in prison.

The army, a major influence in Thai politics, has declared defence of the monarchy to be one of its main duties, and many ordinary citizens also regards it with devotion.

The protest movement has prioritised reform of the monarchy because it believes the institution holds too much power and change is the key to establishing true democracy. They are undertaking their unprecedented challenge at the risk of violent reaction from hardcore royalists.

A crowd of several thousand protesters at Democracy Monument showed their sentiment when a royal motorcade with King Maha Vajiralongkorn passed by.

They turned their backs, put their hands in the air to display their three-finger protest gesture and sang the national anthem.

A small contingent of royalists across the street shouted “Long live the king”.

The king and Queen Suthida were headed to preside over the opening of a new mass transport station elsewhere in the capital. The royal couple have in recent weeks maintained a busy schedule of public events, buoying their followers.

The protesters later wrapped a large white cloth around Democracy Monument on which they wrote messages to the government with their demands and wishes for the future.

The effect of the covering was especially dramatic when lights shone on the monument after dark.

Police initially tried to stop their action, triggering a small clash that left one police officer with a leg injury that caused him to be taken to a hospital.

However, the general atmosphere at the rally was festive as a variety of groups, including secondary school pupils and feminists, promoted their causes.