Mass confusion over loophole which may allow dual British-Australian citizens to travel home on expired passports

The UK Home Office has warned travellers against exploiting a loophole which could allow dual citizens to travel back home on an expired British passport.

Britain's Electronic Travel Authorisation (ETA) scheme will be fully enforced from today, meaning travellers from dozens of countries, including Australia, need to pay £16 ($32) for a visa waiver to enter England, Northern Ireland, Scotland or Wales.

British and Irish citizens won't need to apply for an ETA to visit.

READ MORE: Lucy earns more cash trading Pokémon cards than from her 9 to 5 job

Do you have a story? Contact reporter April Glover at april.glover@nine.com.au

Instead, dual Australian-British nationals have been told they need to travel on a valid British passport or certificate of entitlement to avoid problems like being denied boarding.

However, the UK government stated some airlines may allow British expats to travel on both an expired UK passport and a valid Australian passport.

"The personal details on both passports must match," the government wrote in an update on its website.

"It is the carrier's decision whether to allow you to travel."

Qantas is among the airlines which will temporarily accept expired passports from dual citizens issued in 1989 or later.

It is unclear when this update was posted on the UK government's website.

This advice is incongruent with the warnings issued to dual citizens ahead of today's changes.

A Home Office spokesperson told nine.com.au that some carriers may accept expired British passports "at their own discretion" but still advised dual citizens to have a valid UK passport.

"We recognise that this is a significant change for carriers and travellers, but we have been clear on requirements for dual British citizens to travel with a valid British passport or Certificate of Entitlement, in line with those for all British citizens," the spokesperson said.

"At their own discretion, carriers may accept some expired British passports as alternative documentation. Separately, individuals who have previously had a British passport can apply for an emergency travel document if they urgently need to enter the UK.

"In line with current practice, on arrival at the UK border, Border Force will still assess a person's suitability to enter the UK and conduct additional checks if required."

READ MORE: David sold his home for $2 after 'traumatic' new rule forced him out

READ MORE: Timeline of events that led to Andrew Mountbatten-Windsor's arrest

The conflicting information has caused mass confusion among expats hoping to visit home after today.

Dozens of dual citizens contacted nine.com.au to reveal they had rush-ordered passports or were considering renouncing their British citizenship.

The HM Passport Office recommends people do not book travel or apply for visas until they have their British passport.

A standard passport is £108 ($215) for an adult, and £70 ($138) for a child, plus a £19.86 ($38) courier fee.

Nine.com.au has contacted the British High Commission for comment.

What is a certificate of entitlement?

A certificate of entitlement can be used instead of a British passport and is proof of your right to dwell in the UK.

Importantly, you cannot get a certificate if you already have a British passport or a valid certificate of entitlement in another foreign passport.

It will cost £589 (approx. $1163) for anyone applying outside the UK and it can take around three weeks for your application to be approved.

NEVER MISS A STORY: Get your breaking news and exclusive stories first by following us across all platforms.

• Download the 9NEWS App here via Apple and Google Play
• Make 9News your preferred source on Google by ticking this box here
• Sign up to our breaking newsletter here