Another no-warning blast from Mary Lou.

You’d think Sinn Féin could find somebody to telephone the poor Ceann Comhairle and give him the heads up.

Seán Barrett seemed to be caught on the hop, although we’re not quite sure whether this was by accident or design.

The Ceann Comhairle was slow to act when Mary Lou proceeded to detonate a list of alleged offshore account holders in the middle of a packed Dáil chamber yesterday morning.

Actually, when we say packed, we really mean sparsely populated. Even the Taoiseach had to sit on his own for most of Leaders’ Questions.

Had he known Mary Lou was going to stage another spectacular , he would have taken in a few ministers for protection.

But then, how was Enda to know she would switch her weekly stunt from Thursday to Wednesday?

It's normally Joan Burton who absorbs the onslaught from across the floor.

She doesn’t seem to mind it at all. In fact, the Tánaiste returns fire with alarming relish.

It’s hell for backbenchers cowering in the trenches when Joan and Mary Lou have to be dug out of each other.

Furthermore, Enda would have been feeling very chilled out yesterday morning, having spent an agreeable evening at a Christmas shindig in Dublin's Pantibar with Cork TD Jerry Buttimer and other members of Fine Gael's LGBT group.

(We have it on disreputable authority that when the Taoiseach was given the name of the venue he thought he was off to a lingerie party and had hoped to pick up a stocking filler for the missus. But he got over his disappointment and enjoyed the festive drinks with his colleagues.)

The Taoiseach turning up at one of Dublin’s most popular gay bars caused quite a stir on social media, where some people said, rather unkindly, that Enda’s appearance was a stunt.

But if it was, nobody was talking about it in Leinster House, where Mary Lou McDonald once more demonstrated her superiority in the age old art of political distraction.

Give her a mirror and she’d probably try to upstage herself.

The session began with a return to the issue of homelessness. Fianna Fáil's Micheál McGrath, standing in for his party leader, said that if the death this week of homeless man Jonathan Corrie "is to mean anything, it has to be a catalyst for change".

The Taoiseach didn’t disagree with him.

There wouldn't have been much surprise had Mary Lou (Gerry Adams is on a trip to the Middle East) kept up the pressure on the Government's response to the growing homelessness crisis, which is affecting individuals and families in the private rental sector.

Perhaps she would address the state of our ambulance service. Or maybe she might have raised the case of the women who suffered the appalling procedure of symphysiotomy and are now very unhappy with the redress package which was put in place for them.

Maureen O'Sullivan of the Technical Group later raised this subject, pointing out that the Government has ignored recommendations from the United Nations Human Rights Committee on the implementation of the scheme.

Systematic assault

She quoted the chairman of that committee who said: “I simply don’t understand how the State can look the other way at what seems to have been systematic assault on people who weren’t in a position to resist or even give consent in many cases. We called for prosecutions explicitly and I would hope, I have to hope, that the recommendation won’t be ignored.”

He shouldn’t hope. Because the Taoiseach gave him no cause for it yesterday.

Nor did he have an answer for O’Sullivan when she asked why there has been no focus on the “perpetrators” who inflicted such harm and pain on these blameless women.

But back to Mary Lou McDonald, with a nice list of options to choose from if she wanted to get tough on the Taoiseach. Why should Joan have all the fun?

Whereupon she brought up the dreaded Ansbacher accounts, which some of us first heard about nearly 20 years ago at the McCracken tribunal.

There have been many investigations into them since then.

However, Mary Lou was most anxious to tell the Dáil about allegations made by a whistleblower about named senior politicians whom he alleges held offshore Ansbacher accounts.

A curious subject to bring up, given that the Public Accounts Committee is still actively considering what to do about the dossier in light of recent legal advice.

McDonald is a member of the PAC and her solo-run yesterday annoyed quite a few of her colleagues on this independent Dáil Committee.

Deliberate fashion

In the middle of her contribution on this file of allegations – which has been investigated on a number of occasions down through the years, she named the people mentioned in it in a very deliberate fashion.

This took the rest of the chamber by surprise.

However, she was at pains to point out “it’s not a case of me making allegations against anyone . . . but they come from a very credible source.”

In naming politicians, some of whom saw their heyday in the 1970s and most of whom are long retired from active politics, Mary Lou stressed she was just “echoing the serious allegations that have been brought forward by the whistleblower that are quite serious.”

Among those names was an “S Barrett. Mary Lou said it slowly and clearly, so we could get the full import.

The Ceann Comhairle intervened. “Sorry, are you making these allegations in the chamber?”

One wondered if Seán Barrett had been holding back, reluctant to take on the Sinn Féin deputy leader, who has been doing her best to drive him to distraction with distractions.

And he snapped, rather sourly: “ I wish to state quite categorically, in case anybody is under any doubts when you say ‘S Barrett’, it doesn’t apply to me’’.

No. That concerns wholly unsubstantiated allegations against one Sylvester Barrett, a Fianna Fáil minister back in old God's time.

You have to hand it to Sinn Féin, the party which likes to remind people that their colourful legacy is not up for inspection.

This leaves members free to focus on dark periods they might see in other party’s political pasts, while roundly condemning anyone who tries to shine a similar light on the murkier aspects of Sinn Féin’s past.

Whistleblowers who do not criticise the party or the republican movement are embraced.

Those who dissent are not so royally entertained, as Maíria Cahill discovered.

Just because they have no legacy to stand on, doesn’t mean you can’t step on their toes.

Another tour de force from Mary Lou.