A number of political demonstrations are planned to take place on Sunday 4 August mainly focused in the Dusit, Pom Prab, and Phra Nakorn districts of Bangkok. Several tourist attractions are located in these 3 districts including the Grand Palace and Wat Po.
The political situation in Thailand is unpredictable and sometimes volatile. Over recent years there have been instances of civil and political unrest resulting in large demonstrations and in some cases violence. Take care at all times and avoid any demonstrations or large gatherings.
Authorities in Thailand have implemented the Internal Security Act from 1-10 August, which will lead to an increased security presence in these locations and there may be local disruption to traffic during this time. You should avoid large gatherings and demonstrations.
https://www.gov.uk/foreign-travel-advice/thailand/safety-and-security