Just over three years into a five-year contract, Matthew Elderfield (47) surprised everyone in the financial sector yesterday by declaring his intention to leave the Central Bank in October and return to the UK.

While nobody thought that the Englishman would spend the rest of his career here, there was genuine surprise at the timing of his announcement.

It was only four weeks ago that Elderfield shared a platform with Minister for Finance Michael Noonan to announce performance targets for lenders designed to deal once and for all with mortgage arrears.

There was no detail provided on what “other interests” he might be pursuing but the speculation suggested a move into the private sector rather than another role in financial regulation or supervision.

Clue
The clue is in the line that says he will "step away with immediate effect from involvement in supervisory and other issues if and where a conflict could be perceived".

There’s no doubt that Elderfield has worked hard during his relatively short spell here and greatly enhanced his CV from his time on Dame Street.

But how should we rate his contribution to resolving the financial crisis in Ireland over the past three years and restoring the credibility of the regulator?

Elderfield came to Ireland at a time when the reputation of the country’s financial sector was in tatters after years of lax regulation. He made no secret of the fact that he felt the Central Bank was under-resourced and lacked sufficient skills in certain key areas to tackle the crisis that was unfolding. He also argued for greater powers of enforcement.

Elderfield made his mark early on by appointing administrators to Quinn Insurance Ltd at the end of March 2010 over concerns about its solvency ratios. This set in train a series of events that ultimately led to the collapse of Sean Quinn's business empire.

It was a gutsy move and Elderfield remained resolute in the face of enormous pressure from various quarters.

His "show me the money and we will take a different approach" quote in response to claims by Sean Quinn that he could sort out the issues around the insurer was particularly memorable. Nothing that has happened since with the Quinns suggests that Elderfield's move was unjustified.

Elderfield is also credited with implementing rigorous stress tests on the banks a couple of years ago.

On the flip side, some would argue that the Central Bank has been a tad heavy-handed in the raft of fines it has issued to various investment advisers for what are perceived as relatively minor breaches of rules.

Those involved in the IFSC also claim they are over-burdened by regulations that are more suitable to high street banks rather than the specialist work they undertake.

In response, Elderfield might point to the collapse of Depfa Bank in the IFSC as justification for imposing rigorous regulation. It might also be argued that the regulator dropped the ball in relation to the collapses of Custom House Capital and Bloxham Stockbrokers.

Arrears
And there are many who feel that it has taken too long to get to grips with the mortgage arrears issue. We're five years into the financial crisis and our banks still haven't faced up to this major problem.

At the end of December, 94,488 private residential mortgage accounts were in arrears of 90 days or more. That’s 11.9 per cent of the total. Another 28,421 buy-to-let properties are in arrears of three months or more.

To date, the banks have been content to kick the can down the road.

The regulator said the new targets will be backed by “rigorous new provisioning standards” and the “possible” imposition of higher capital requirements.

Having finally set the ball in motion to deal with the arrears crisis, Elderfield’s departure is hardly helpful to its implementation and it will pass to his successor to get it over the line.

Noonan said Elderfield was leaving at a time when “normality” is returning to the financial system. He might have added that the Englishman has helped to restore the reputation of the regulator.

These might ultimately prove to be Elderfield’s legacy here.