In a no-deal Brexit scenario, clocks in Northern Ireland could end up being an hour different to those in London, or Dublin, if European Commission proposals to end daylight saving go ahead.

Commission President Jean-Claude Juncker presented the idea of scrapping daylight saving in his State of the Union speech in September, pledging to end the twice-yearly time switch in 2019. He said Europe-wide research shows the current system is unpopular.

On Monday, the U.K. parliament’s EU internal market sub-committee published a report recommending the House of Lords issue a “reasoned opinion” objecting to the Commission’s proposal, noting the potential negative impact on the Irish border issue.

“If the U.K. decided [under a no-deal scenario] to maintain summertime arrangements, Northern Ireland would have to choose between having a one-hour time difference for the year either with the Republic of Ireland or with the rest of the UK,” it says.

The sub-committee’s report raises concerns over the proposal as it does not comply with the EU principle of subsidiarity. “We consider that [EU] member states are best placed to determine the necessity of seasonal time changes within their own territories,” it states.

“The European Commission’s proposal to end seasonal time changes goes beyond its remit and is not in compliance with the principle of subsidiarity,” Larry Witty, the sub-committee’s chair, said. “We are therefore recommending that the House of Lords issues a reasoned opinion.”

The report also questions whether there’s an actual need for the plan to scrap daylight saving time. “The 4.6 million respondents to the Commission’s consultation exercise represented less than 1 percent of all EU citizens, and response rates varied drastically between member states,” it notes.