Ireland's economy is on course to be the best performer in the European Union for the fifth consecutive year, but concern about the vulnerability of the economy to an unruly British exit from the bloc has weighed on consumer sentiment.

The KBC Bank Ireland/ESRI Consumer Sentiment Index was 96.5 in December, unchanged from the previous month. The index hit a 17-year high of 110.9 last January.

The report's authors said the stability appeared to be as a result of consumers' "considerable difficulties in assessing both the likelihood and possible impact of potentially important changes in their circumstances in the year ahead."

Sentiment appears to be at a tipping point depending on whether Britain crashes out of the European Union without a deal on March 29, they said.

Only 26 percent of respondents said they expected a stronger Irish economy over the next 12 months compared with 32 percent expecting weaker conditions - the first time there have been more pessimists than optimists on this question since 2013.

However, 26 percent consumers reported an improvement in their household finances over the past year compared with 20 percent reporting a deterioration.

(Reporting by Conor Humphries; Editing by Hugh Lawson)