Mary Harney cannot hide on the other side of the world for much longer.

As her Lord of the Rings tour of New Zealand comes to an end, the Minister for Health should be back just in time for Brian Cowen's long-awaited cabinet reshuffle on Tuesday.

Given the controversy that has erupted in her absence, she will not be expecting much of a homecoming -- and equally, the Taoiseach should be in no doubt of the political backlash that will follow if he flunks this golden opportunity to sack her.

disgraceful

The Cardinal Brady affair and the St Patrick's Day festivities may have temporarily knocked it off the front pages, but the scandal of Tallaght Hospital remains as shocking and disgraceful as ever.

Over a week after the story first broke, nobody has come up with a convincing explanation for how 58,000 X-rays went unread by radiologists for four years and 3,500 letters from GPs asking for appointments for patients were not even opened.

The only thing that Harney, Brendan Drumm and the hospital itself can agree upon is that everybody is to blame except themselves.

One fact, however, is now beyond dispute. Harney was told there was a problem in Tallaght as long ago as last December and did nothing to either find out the scale of the crisis or make sure it was sorted out.

That alone should be a resigning matter -- but as she rode around in a carriage and waved to the crowds like Queen Elizabeth in Auckland, the Minister looked like a woman determined to brazen this out just as she has with so many other health fiascos over the last five years.

Ironically, from a financial point of view this scandal could turn out to be one of the best things that has ever happened to her.

The Minister has indicated that she will sue the radio station Newstalk over the false slurs on her character made last week by the veteran journalist Nell McCafferty.

Given the way the libel laws work in this country and the people involved, that could make for a very interesting day in court indeed.

So can Harney really get out of this one?

Brian Cowen, for reasons best known to himself, has publicly insisted that he has full confidence in her.

There are fears that she would resign her Dail seat rather than hang around on the backbenches, forcing yet another by-election and almost certainly eroding the Government's fragile majority even further.

There are two reasons why the Taoiseach may be forced to change his mind between now and Tuesday.

catastrophic

The first is the intense pressure from FF backbenchers, who are fed up with sharing the political blame for Harney's constant bungling and catastrophic public image.

They point out that as an independent TD, the ex-PD leader has no more right to a cabinet position than Jackie Healy-Rae does -- and while few of them fancy the job themselves, they insist that it should be returned to one of their own.

The second reason is much more serious. Between now and May, the backlog of unread X-rays in Tallaght will carry on being processed.

This means that in theory at least, another case of delayed cancer diagnosis could emerge at any moment -- graphically illustrating the human cost of Harney's failure and creating a public uproar that would only be satisfied by heads on plates.

There is a simple way for Cowen to avoid this nightmare scenario.

By appointing a fresh new face, untainted by the mistakes of the past, as minister for health on Tuesday, the Taoiseach can send a powerful signal that he is prepared to put the good of the country above personal loyalty.

If Harney had been truly remorseful for the Tallaght scandal, she would be back in Ireland by now.

Her refusal to break off her tour Down Under suggests that she now believes she can commit almost any blunder and get away with it.

Brian Cowen is the one man who can prove her wrong -- and the decision he makes about her future next week could well decide how long he gets to keep his own job.