The news that the four biggest accountancy firms in the State – PricewaterhouseCoopers, KPMG, Deloitte and EY – had combined fee income of almost €1 billion last year would have come as a surprise to many. But probably less so for their clients who paid the fees in question.

It is a very large sum of money and difficult to put in a meaningful context. In crude terms, it accounts for about a half of 1 per cent of Gross Domestic Product, the value of all the goods and services produced by the economy.

This in turn allows a back-of-the-envelope comparison with the UK where, according to Accountancy Age magazine, the big four firms earned £6.8 billion last year. In GDP terms this accounts for about a quarter of 1 per cent of UK GDP.

Accountancy – and in particular the sort of high-end audit, tax and corporate advisory work dominated by the big four firms – would appear to be a much bigger part of the Irish economy than the UK economy. Twice as important, in fact.

There are several possible explanations for this surprising finding. Could Ireland have a proportionally greater number of the sort of companies that need the specialised skills that the big accountants provide? It seems unlikely given the extent to which financial services dominate the British economy.

Do the big four firms here have a much bigger share of the market than their counterparts in the UK?

It’s possible. The British competition watchdog has been trying for years to address the dominance of the big firms, but with limited success.

If the explanation is not market dominance, then it has to be that Irish firms just squeeze higher fees out of their clients. One generally leads to the other anyway.