What are the PCR test requirements for traveling from the UK/EU to Thailand, especially regarding flight delays?

Travelers flying from the UK/EU to Thailand must have a PCR test taken within 72 hours of their departure time. This rule applies specifically to the first flight from the UK. It's important to note that for those transiting through Singapore, the PCR test must be taken within two days of the flight to Singapore, not just based on arrival in Thailand. Delayed flights should not affect the timing of the PCR test, as it is linked to departure time.