Britain has begun issuing passports with the words "European Union" removed from the front cover - despite Brexit being delayed and its political leaders deadlocked over how to extricate the country from the bloc.

The interior ministry has said that a longstanding decision to start introducing passports without reference to the EU had gone ahead from March 30, the day after the original date for Brexit.

In an apt sign of the befuddling circumstances around Brexit, Britain's interior ministry confirmed that some newly-issued passports now omit references to the EU atop the cover while others still bear the bloc's name.

It said the discrepancy was due to an attempt to save public money and insisted both designs would be "equally valid for travel".

"In order to use leftover stock and achieve best value for the taxpayer, passports that include the words 'European Union' will continue to be issued for a short period," a spokeswoman added.

British passports have become ensnared in the country's Brexit divisions after the government announced in 2017 it would return to traditional blue passports "to restore national identity".

The travel documents had dark blue covers from 1921, but Britain switched to burgundy from 1988, in common with other passports in what was then the European Community.

Brexit backers are thrilled by the highly symbolic change, while those who support remaining in the bloc have mocked their excitement.

Last year it emerged that Franco-Dutch company Gemalto had won the contract to make the new blue passports, prompting fury from Brexit campaigners and more ridicule from Remainers that a British company was not chosen.

The new production contract is to begin in October 2019, with the passports currently being issued without reference to the EU on them still in the burgundy colour.