Warning that Northern Ireland could end up in a different time zone to UK in Brexit plans

Border Communities Against Brexit holding protests on Old Belfast Road in Carrickcarnon on the northern side of the Irish border, between Newry and Dundalk. Photograph: Niall Carson/PA. - Credit: PA Archive/PA Images

Brexit could lead to Northern Ireland operating in a different time zone to the rest of the UK, peers have warned.

The European Parliament voted last year in support of a proposal that would put an end to the twice-yearly changing of the clocks to accommodate extra daylight hours.

Under an EU directive, all 27 states currently switch to summer time hours on the last Sunday of March and back to Greenwich Mean Time (GMT) on the last Sunday of October – a pattern the UK follows.

But under a potential swap by Brussels to a “double summer time” arrangement, Lords have warned that the Withdrawal Agreement could see Northern Ireland legally obliged to be one hour ahead for six months every year.

It would mean the 1.8 million people living in the six counties would follow summer time hours, even when those in Great Britain wind their clocks back by 60 minutes in the autumn.

Any EU-wide shift in timekeeping would apply to Ireland and, due to the terms of the PM’s divorce treaty, Northern Ireland might have to follow suit, peers have suggested.

“Were this proposal (for double summer time) to become EU law under its current single market legal basis, Northern Ireland may be obliged under the terms of the Withdrawal Agreement and the protocol on Ireland/Northern Ireland to align with the EU and thus institute a time border with Great Britain,” said the Lords’ EU internal market sub-committee in its report, Clock changes: is it time for change?

The group of cross-party peers have called on the government to “give urgent further consideration” to the impact the Brexit agreement could have if the EU does decide to make the summer time switch permanent – and criticised ministers’ lax approach to what could be a significant change for the UK.

“Our inquiry has demonstrated that any such decision at EU level would have implications for the UK, notwithstanding UK withdrawal from the EU,” wrote the peers.

“The nature and significance of such implications is not, however, well understood – not least by the government.”

Baroness Donaghy, chair of the committee, said there was also the possibility that Ireland could face a situation where it has different time-zones on either side of the border.

“So far the government has stuck its head in the sand on the EU Commission’s proposal, hoping that it goes away,” she said.

“However, if it doesn’t, we could be caught unaware and unprepared to make a decision, leaving the island of Ireland with two time zones at different times of the year and causing difficulties for people and businesses in Northern Ireland.”

Business minister Kelly Tolhurst, giving evidence to the committee last year, said: “Anything that would create a time border in Northern Ireland we are completely opposed to, and so is the Irish government.”