Five facts you need to know about your passport

As it emerged up to 80,000 Britons could be banned from US flights due to a passport changes, here are five more things you may not know about yours

A biometric passport is required for visiting the US

Passport validity needs only to cover the duration of your trip, up to and including the day of return to the UK

The rule applies to British passport-holders travelling within the EU, although ultimately it is the responsibility of the traveller to check the requirements of the country they are travelling to.

There has been a handful of cases in recent years of airlines refusing passengers on the grounds of their passport validity. Jonathan Rickard was turned away from the easyJet check-in desk at Gatwick in June 2013 for his flight to Larnaca, therefore missing his friend's wedding. The airline stated that his passport was due to expire in two months and was therefore not valid for the trip. It later admitted its mistake and refunded his trip.

Last December, British Airways cited new migration laws as the reason for turning away a family from a flight from Gatwick to Salzburg. It stated that the Austrian government had recently introduced new rules that insisted on three months' passport validity. A spokesperson at the Austrian Embassy later confirmed that "British passports only need to be valid during the stay when travelling to Austria." The new rules apply to non-EU citizens.

However, many countries outside Europe require a minimum period of passport validity fo three to six months, often calcuated from the date of departure. Those insisting on six months include Turkey, Thailand, Egypt and Brazil. South Africa and New Zealand require one month from the date of exit. Many countries also require at least one clear passport page at immigration. To check national requirements, go to gov.uk/foreign-travel-advice

It is unknown whether Brexit would have an affect on passport validity within the EU

While there has been a surge of applications for dual-nationality passports, notably Irish, since the announcement of June's referendum, there has been no announcement as to whether a "leave" vote would alter the requirements for British passport-holders travelling within the EU. There would, however, be no change to terms outside the EEA and EU.

You can buy extra time on your passport

If your pasport still has nine months left to run, it is possible to renew it now and get full credit for unexpired time. For example, if your passport is due to expire on 6 February 2017, renew it today and receive a new passport that will expire on 6 February 2027. Fees were cut in September 2012 from £77.50 to £72.50 for a 32-page adult passport, a cost that was guaranteed for two years but has yet to be increased. Using the Post Office's Check and Send service adds around another £10 but is recommended, as is avoiding the peak summer months for renewals.

It is legal to have two passports

British nationals can legally hold two passports. The practice is useful for frequent travellers who may need to send one off for visa applications while still needing another to travel. However, you will need to provide supporting evidence for the requirement, for example a letter from an employer. It can also be useful when your travel history has the potential to affect your entry eligibility. For instance, an Israeli passport stamp can prevent entry to countries such as Iran and Lebanon.

The US recently introduced rules prohibiting visitors from applying for an Esta if they have visited Iraq, Syria, Iran, Sudan, Libya, Somalia and Yemen since 11 March 2011.

Travellers holding a valid visa rather than an Esta (Electronic System for Travel Authorization) do not need a biometric passport to enter the US

New passport rules insisting on biometric passports - issued from 2007 onwards and including an embedded chip containing your personal details - for travel to the US mean that tens of thousands of British travellers will face being turned away at the check-in desk for their transatlantic flight this summer. This is largely because Esta data is stored electronically, whereas visas are stored electronically as well as issued in paper format and are presented with the passport at check-in and border controls. To check whether you need an Esta or a visa to enter the US, go to the official Esta application page.

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