Sri Lanka, Feb. 23 -- British and Irish dual nationals may be able to use their expired British passports, along with a valid second passport, to enter the United Kingdom under new temporary measures - but only at the discretion of airlines and other carriers.

From Wednesday, dual citizens of the UK and Ireland would previously have needed a valid British or Irish passport, or a costly Certificate of Entitlement, to board planes, ferries, or international trains under controversial new rules.

But the UK Home Office has quietly updated its website, saying carriers could now "at their own discretion" accept an "expired British passport as an alternative document".

The temporary guidance states carriers such as airlines and ferry operator...