Czech Prime Minister Petr Necas was forced to quit on Sunday (June 16) by a graft and spying scandal involving his closest aide, pitching the European Union member state into a period of uncertainty over who will form the next government.

Under the Czech constitution, the whole government will now have to step down, and there is likely to be horse-trading between the governing coalition, the opposition and the president before a replacement is in place.

Necas quit days after prosecutors charged the head of his office, Jana Nagyova, with bribing members of parliament and ordering intelligence agents to spy on people.

The scandal has a personal element for the prime minister: one of the surveillance targets, according to lawyers involved in the case, was the prime minister's own wife, Radka. The two are filing for divorce.

Necas has said he knew nothing about the surveillance, but the charges were so toxic that his coalition partners signalled they could no longer support him.

He said his party would try to form a new government, led by a different person, to rule until a scheduled election next year. However, it was unclear if that plan could muster enough support in parliament.

Necas and his administration will stay on as caretakers until a new government is installed. President Milos Zeman will have an important say in who takes over. If after three attempts there is no viable government, or the parliament agrees to dissolve itself, an early election will be held.

An early election would favour the opposition Social Democrats, who, according to opinion polls, are more popular than the government.

The anti-corruption operation that brought down Necas was the biggest in the Czech Republic for 20 years.

Last week's operation was, in part, the result of Necas's own reforms: under his watch, newly appointed prosecutors were given a free hand to go after corruption cases.

Presented by Adam Justice