Sri Lanka's ousted Prime Minister Ranil Wickremesinghe Image Credit: Reuters

Colombo: Sri Lanka has plunged into a constitutional crisis after its president sacked the prime minister and appointed a controversial former strongman ruler in his place.

Here is a timeline of events leading up to the standoff that could see former president Mahinda Rajapakse return to power:

2015

January 8: Rajapakse loses presidency
Rajapakse loses a presidential election to Maithripala Sirisena on January 8, 2015, after a decade in power during which he ended a brutal war with Tamil separatists amid widespread allegations of war crimes with thousands of civilians killed. His term was also tainted by corruption accusations. The 72-year-old denies any wrongdoing in the conflict or in the handing out of contracts but he and his family have been under investigation and face international criticism.

August: Parliament return
Rajapakse becomes the first Sri Lankan former president to make a return as a member of parliament following a legislative election in August 2015. But his Sri Lanka Freedom Party (SLFP) is beaten into second place by Ranil Wickremesinghe’s United National Party, dashing his hopes of securing new power as prime minister.

2018

February 10: Fragile coalition boosts strongman
The coalition between Sirisena and Wickremesinghe is fragile from day one, with political divisions and economic difficulties helping Rajapakse’s SLFP faction score a spectacular victory in local elections on February 10, 2018. Rajapakse’s party immediately demands new national elections.

August 24: Fightback after corruption case
A special anti-corruption court launches operations on August 24 with a case against Rajapakse’s former chief of staff who is accused of siphoning off $3 million (Dh11 million) from a construction deal. Another Rajapakse official has already been jailed for three years for graft.

Two of the former president’s three sons are also accused of graft. Rajapakse says he is the victim of a “political witch hunt”.

Tens of thousands of his supporters gather in Colombo on September 5 demanding new elections and five days later Rajapakse holds talks with India’s Prime Minister Narendra Modi in New Delhi.

October: Prime minister sacked
Out of the blue but under growing pressure, President Sirisena sacks coalition ally Wikremesinghe as prime minister and installs Rajapakse. With Wickremesinghe resisting his ouster, the move plunges Sri Lanka into deep turmoil likely to end up in bitter court challenges, with a presidential election due in 2019 and legislative polls the following year.