'No backsliding' on Brexit promise, Irish PM warns

"As the negotiations move forward, we will continue to rely on your support and solidarity as we work to ensure that what has been promised in theory is delivered in practice. There can be no backsliding," he said.

Avoiding a hard border in Northern Ireland that could tear apart communities only recently brought together by the peace agreement was one of the key issues in the first phase of Brexit talks.

Varadkar pointed out that the citizens of Northern Ireland will likely remain EU citizens because of their unique status under the Good Friday Agreement putting an end to violence there.

The taoiseach said it was important that the deal reached in December is fully reflected in the withdrawal agreement that is now being formalised in a legal text.

EU future

The Irish centre-right politician was the first to speak in a series of speeches by EU leaders on the future of Europe in the European Parliament.

Varadkar pointed out that in the future all EU member states will be small states in comparison to the megacities and highly-populated countries of Asia, China and the global South.

"So, we're going to need to stick together if we are to protect what we have and export our values and world view," he said.

"If it wasn't for Europe, our country would not be present on the world stage," Varadkar added.

Varadkar, at 38 the second-youngest prime minister in Europe, said he supported making the so-called Spitzenkandidat system permanent.

The system lets EU-level party families nominate top candidates, with the winning party's candidate becoming the president of the European Commission. This is how Jean-Claude Juncker was chosen in 2014.

Varadkar said that choosing the leading positions in the EU should be democratised. He said he also supported an EU-wide list for the European Parliament for the elections in spring 2019.

"Let's get people in cafes in Naples and restaurants in Galway talking about the same election choices," he said.

On the EU budget, Varadkar said that as a net contributor, Ireland supports maintaining the structural funds to eastern and central Europe, the common agriculture fund, Erasmus, funding for research and the European Investment Bank. He said these programs should be protected.

"For new programmes, we should use new money," he said.

He added that Dublin would make a larger contribution, if projects important for Ireland would not be cut.

Varadkar also said he supported the idea of an EU 'Marshall Plan' for Africa to stem the flow of migrants, and to avoid a larger wave of people arriving from Africa seeking asylum or a better life in Europe.

Defence of Ireland's taxes

Varadkar sought to defend Ireland's controversial corporation tax system in the EP, which is criticised for being a tax haven for large tech companies in Europe.

In 2016 the EU Commission ordered US tech giant Apple to pay back Ireland €13 billion in back taxes.

Varadkar said it should be national governments and parliaments should set their own taxes.

But he added, that large corporations should not be able to avoid paying taxes.

"That's as true for American tech companies as it is for European car manufacturers, or for international aerospace and defence companies," he said, adding that Ireland has taken steps to close loopholes in Irish tax rules.

However, he added that closing loopholes should be done on an international basis through the Organisation of Economic Cooperation and Development (OECD). "Europe should not give advantages to our competitors by acting unilaterally," Varadkar said.

A second referendum

After Varadkar rose to speak, Juncker told MEPs the UK should re-apply for EU membership after Brexit.

"Even if the British leave under Article 50, then Article 49 would allow them to join again and I would like that," Juncker said.

A day before, European Council president Donald Tusk had told MEP that the UK would be welcomed to stay an EU member if it changed its mind.

"We haven't had a change of heart. Our hearts are still open for you," Tusk said.

Varadkar later told reporters that any possible second referendum was for the UK to decide.