Donald Trump may soon find himself on the receiving end of a "visa war" that could have dire consequences for trans-Atlantic travel and European tourism. On Thuesday, EU lawmakers voted to force Americans to apply for visas when traveling to Europe in response to Washington refusing to allow all Europeans to travel to the States visa-free.

The vote by show of hands was the latest in an ongoing “visa war” between Brussels and Washington DC, which now looks set to come to a head after MEPs today agreed that US nationals crossing the Atlantic should require additional travel documents as long as citizens from five EU countries (Bulgaria, Croatia, Cyprus, Poland and Romania) are kept from entering America without a visa. A European Parliament source told Telegraph Travel this was a “serious negative step in the EU-USA visa war”.

Following today's vote, the EU Commission now has two months to reintroduce visas for Americans wishing to travel to Europe, after MEPs agreed the EU is now “legally obliged” to suspend the Visa Waiver Programme (VWP) with the US for a year after the US administration failed to meet a deadline to respond something called visa reciprocity. Parliament and the European Council will have the chance to object to anything put forward by the Commission according to the Telegraph.

The resolution passed despite warnings from the European Travel Commission (ETC) of the damage a visa war with the US might have on the continent’s tourism industry. “We fully understand and respect the visa waiver reciprocity mechanism embedded in European legislation to ensure that all nationals of Member States part of Schengen can benefit on equal terms from exemption of visa requirement,” said Eduardo Santander, executive director of the ETC, in a joint letter with Michael de Blust, secretariat of the Network for the European Private Sector in Tourism, to MEPs.

“However, we are very concerned about the economic and political impact of a suspension of visa waiver for US nationals. “Making it more difficult for US citizens to travel to Europe would certainly deprive the European travel and tourism sector of essential revenue, and put thousands of European jobs at stake in one of the few sectors which experiences a strong growth in employment.”

As we reported at the time, it was in April 2014 that the European Commission was first made aware that the US - along with Australia, Brunei, Canada and Japan - was failing to ensure the same visa waiver rights for its citizens that Europe offered in return. The Commission then gave the countries a deadline of two years before retaliating. Since, Australia, Brunei and Japan have all lifted their visa requirements, with Canada set to do the same by the end of the year, but the US has failed to act.

There has not yet been a response to today’s vote from the US but the State Department’s Bureau of Consular Affairs has said in the past that Bulgaria, Croatia, Cyprus, Poland and Romania do not yet meet security requirements for the US VWP. Canada also imposes visa requirements on Bulgarian and Romanian citizens, but it has announced that they will be lifted in December.

Since the imposition of a visa regime is perceived as a major hurdle to free travel, the implementation of the MEP vote would likely lead to a dramatic drop in airline travel across the US and Europe, coupled with a plunge in tourism and associated reveue. As a country looking to boost its tourism industry will often look at loosening any existing visa requirements, the opposite may suggest that the European decision may have political overtones and be in response to Trump's aggressive anti-immigration regime.