Update | Thailand in power vacuum as court rules February’s election results invalid

Thailand's Constitutional Court ruled February's general election invalid, in a further roadblock to Prime Minister Yingluck Shinawatra's efforts to form a new government and leaving the country in political limbo.

The court judges ruled by six votes to three that the February 2 election was unconstitutional because voting failed to take place on the same day around the country. Yingluck had called an election on February 2 in a bid to defuse anti-government protests, and since then has headed a caretaker government with limited powers.

It is unclear when a new election will take place. While the court ruling further delays the formation of a new government, it also offers a possible exit from the political stalemate - if the opposition agrees to end its boycott of the ballot box.

"The commission could discuss with the government about issuing a new royal decree for a new date or we could ask the heads of all political parties to decide together when best to set the new election date," said Somchai Srisutthiyakorn, an Election Commission member.

Anti-government protesters had stopped voting in about a fifth of constituencies, and in 28 of them voting was not possible at all because candidates were unable to register.

But Yingluck's supporters fear she will be removed from office before another vote is held. She has been charged with negligence by the National Anti-Corruption Commission in connection with a rice subsidy scheme, and could face an impeachment vote in the upper house of parliament within weeks.