By James Helm BBC correspondent in Dublin

How rapidly political times have changed in Ireland.

It is only four months since Prime Minister Bertie Ahern and his Fianna Fail Party were swept back into power in the general election.

Personally popular, and having presided over a golden era of Irish economic growth, Bertie - as everyone here simply refers to him - was triumphant at the polls.

Fast forward to the present day: political pressure on the Fianna Fail leader is mounting, the criticism growing.

Things are starting to stick to the man they often called the Teflon Taoiseach (prime minister).

And with a second referendum on the Nice Treaty on European Union expansion fast approaching - the first was lost last year - the timing is pretty awful for Mr Ahern.

Resignation

The Flood Tribunal has cost millions, and the revelations it produced have, at various times, amazed and angered the Irish people

The head of Fianna Fail's campaign for a Yes vote in the referendum on 19 October has resigned.

PJ Mara, who oversaw the successful general election campaign in May, is a casualty of the fall-out from a report into high-level corruption in Ireland.

According to the report, published on 26 September, Mr Mara - the man who memorably launched Fianna Fail's election campaign with the words "It's showtime" - failed to co-operate with the corruption investigation.

Rather than have the affair distract attention from the referendum, Mr Mara has stepped down.

Investigation

The background to all this lies in the Flood Tribunal. In its five years of investigations,190 witnesses have been interviewed.

It has cost millions, and the revelations it produced have, at various times, amazed and angered the Irish people who watched its progress.

The central character in what was an interim report was Ray Burke, a former Fianna Fail minister, whose varied portfolios included justice, foreign affairs and communications.

It says that throughout his political career Mr Burke accepted thousands of pounds in corrupt payments from businessmen.

Favours allegedly were given in return. Property developers were assisted. It is also alleged that in 1989, when Mr Burke was minister for communications, he was paid by a company which had been seeking, and had received, a radio licence.

The tribunal will resume later this year.

Reaction

Mr Ahern says another "no" to Nice would diminish Ireland's reputation in Europe

Mr Justice Flood's report was both clear and damning. So too has been the reaction of Ireland's media.

The Irish Independent's headline refers to Ray Burke, beside a photo, as "minister for corruption".

Prosecutions may follow. And many others who appeared before the tribunal have been criticised for hindering its efforts. Mr Mara was said by the report to have failed to co-operate with the tribunal.

The Taoiseach has welcomed the report, and called it "profoundly significant," sending out a clear message that anyone acting improperly and illegally in public life will be exposed.

The opposition, however, is highly critical of Mr Ahern.

In 1997, it was he who appointed Ray Burke to the post of minister of foreign affairs, despite allegations circulating at the time.

In his defence, the Taoiseach says that the evidence found by the Flood Tribunal's hard work was not there at the time of the appointment. To make matters worse, though, Mr Ahern has now lost his director of elections, PJ Mara.

Leaked memo

It has been a tough week for the Taoiseach all round: with his Finance Minister, Charlie McCreevy, he has been accused of pulling the wool over voters' eyes in this year's general election.

A memo inadvertently released to the press last weekend showed government plans to trim public spending.

The memo was written shortly after the election; opponents claim the plans for cutbacks had been drawn up well before the election, but could not be made public for fear of losing votes.

Ireland's economy has cooled in recent months, and Mr McCreevy says he is simply practising sane and sensible economics. The net effect though has been mounting public criticism of the government.

All the biggest political parties are advocating a Yes vote, just as they did last time, when the No side triumphed by capturing almost 54% of the vote.

Bertie Ahern says another "No" to Nice would diminish Ireland's reputation in Europe. His worry now must be that in the current political climate, many of Ireland's voters may see 19 October as an immediate and perfect opportunity to give him and those around him a resounding kick.