In mid-June, Paetongtarn Shinawatra, who was then-prime minister of Thailand, made a call to Cambodia’s de facto leader, Hun Sen, to address a recent escalation along the border between the two countries that had left a Cambodian soldier dead.

The call was intended to smooth over tensions, but instead initiated a chain of events that has left Ms Paetongtarn suspended from office and at least 12 Thai civilians dead following a second round of clashes.

Shortly after the two leaders hung up the phone, Hun Sen made the decision to leak the audio recording in which Ms Paetongtarn is heard kowtowing before the veteran politician and criticising a Thai army commander – a red line not to cross in a country where the military has significant power and prestige.

The leaked call was highly embarrassing, showing Ms Paetongtarn used “uncle” – a term of endearment – when addressing her counterpart on the other end of the line.

Her comments drew criticism across Thailand, and a case was quickly petitioned against her at the Constitutional Court, alleging that she violated ethical standards during the call.

On July 1, the court voted 7-2 that she should be suspended until they render a verdict and the country’s interior minister Phumtham Wechayachai took over as acting prime minister.

In the weeks since, Thailand has been consumed with the domestic turmoil caused by the fallout from the leaked conversation, while tensions along the border have continued to rise, finally erupting early Thursday morning in what has been the deadliest face-off between the two countries in decades.

Clashes in May

Before the call, trouble on the border was already simmering.

The disputes boil down to differing interpretations of colonial-era maps drawn more than a century ago by the French – who once colonised Cambodia – and by Siam (modern-day Thailand). The maps had conflicting delineations of the 508-mile border, particularly around a series of important ancient temples.

On May 28, a Cambodian sergeant was killed during a 10-minute shoot-out, following weeks of mounting tensions between both sides.

Before the incident, Thai soldiers had accused Cambodian troops of burning a friendship gazebo in Thailand’s northeastern Ubon Ratchathani province.

Following the skirmish in May, both sides increased the number of troops along the border. However, attempts to resolve the issue through diplomatic means were unsuccessful.

The two countries also imposed a number of restrictions on each other, with Cambodia banning Thai films and TV shows and blocking the imports of produce, fuel and gas.

For its part, Thailand closed its land borders to both tourists and traders.

The same day as the now-infamous phone call, but before its contents were leaked, Cambodia also announced that it had lodged a formal complaint at the International Court of Justice to rule on several of the contested areas along the shared border.

The ICJ had previously ruled in Cambodia’s favour on the 11th-century Preah Vihear temple, which is also claimed by both countries. However, Thailand had previously said that it does not recognise the ICJ’s ruling.

During her conversation with Hun Sen, Ms Paetongtarn pleaded with him not to be “upset or angry” by comments the commander had made where he threatened Cambodia to a “duel” over the border land.

“He just wanted to look tough and ended up saying things that are not helpful to either country,” Ms Paetongtarn was heard saying.

Later on, she also said: “If there’s anything you want, just let me know. I’ll take care of it.”

Many across Thailand criticised her for being too soft with the Cambodian strongman.

“She was compromised by her conversation with Hun Sen whereby she is perceived to have given concessions to him at the expense of Thai sovereignty,” said Thitinan Pongsudhirak, a professor of political science at Chulalongkorn University.

Hun Sen hasn’t commented on why he decided to leak the audio, but he seemed intent on removing Ms Paetongtarn from power.

A week after releasing the tape, Hun Sen said that Thailand “will have a new prime minister within the next three months”, suggesting that he was eager to see a reshuffle in Bangkok.

While Ms Paetongtarn apologised, the damage was already done.

The pro-military Bhum Jai Thai Party (BJT) announced that it would be withdrawing its 69 members of parliament from its coalition with Ms Paetongtarn’s centre-left Pheu Thai Party, leaving her government with barely enough seats to remain in power.

Soon after, the case was lodged at the Constitutional Court and Ms Paetongtarn was suspended.

Initially, she was given five days to respond, but on Wednesday, the court granted her an extension until July 31.

If the court rules against her, she would be permanently removed from office.

Following Ms Paetongtarn’s suspension, there was a week, which experts described as the “calm before the storm”.

Last week, tensions between Cambodia and Thailand returned with a vengeance when three Thai soldiers were injured by landmines along the border in the same area where the incident on May 28 had taken place.

Thailand accused Cambodia of laying down new anti-personnel landmines, which caused the accident.

The mines were not of a type used by Thailand and were laid in a “blatant violation of international law”, the foreign ministry said.

There was then another landmine incident on Wednesday, which led to Thailand recalling its ambassador to Cambodia and expelling the Cambodian envoy.

It also ordered the closure of four border checkpoints between the two countries.

This all culminated in the fatal clashes along the border on Thursday morning, with both sides claiming the other fired first.

Cambodia claims that around 6.30am local time (12.30am UK), Thai soldiers initiated the conflict by advancing on an ancient temple near the border, then deploying a drone shortly after, which fired shots into the air.

The Cambodian side then claims that Thai troops “pre-emptively” opened fire and Cambodian soldiers had “no choice” but to respond, according to statements from both the foreign and defence ministries.

Thailand has said that shortly after 7.30am local time (1.30am UK), Cambodian military drones conducted surveillance of Thai soldiers stationed near the border, and soon after its troops had gathered along the border with RPGs.

Thailand’s National Security Council claimed that Thai soldiers tried to negotiate but were unsuccessful, and Cambodia soon deployed BM-21 rocket launchers and artillery, which hit several civilian areas, including a hospital, a petrol station, and a development centre.

At least 12 civilians, including two children, have been killed.

Thailand also confirmed that it sent six F-16 fighter jets to attack two Cambodian military targets, but the jets have since “returned home safely”.

The current death toll is quickly approaching the last major incident along the border in 2011 when at least 15 civilians were killed.

“As things stand, I don’t see de-escalation coming soon. The real question is how far the fighting might go,” said Tita Sanglee, an associate fellow at the ISEAS–Yusof Ishak Institute in Singapore.

The UN Security Council is set to hold an emergency meeting on Friday over the situation, according to diplomatic sources.

The meeting, requested by Cambodian Prime Minister Hun Manet, will be held behind closed doors at 3pm local time (7pm GMT), the sources said.

Additional reporting by Sarah Newey in Bangkok.