The Guardian’s analysis is based on generational polling data published by Eurobarometer, a collection of cross-country public opinion surveys conducted regularly on behalf of the EU Institutions since 1974.

The survey asks respondents across Europe if they have negative feelings about immigration from outside the EU, breaking the results down by gen Z, millennials, gen X – those born between 1965 and 1980 – and baby boomers – between 1946 and 1964.

Eurobarometer results suggest that attitudes towards immigration have hardened among younger respondents in the four years since the last EU elections, reflecting an overall rise in anti-immigration sentiment across all age groups across the bloc.

In 2019, a third (32%) of Europeans aged between 15 and 24 said they had a negative attitude to immigration, but in late 2023 this figure had risen to 35%. For those aged between 25 and 34, the share of respondents with negative feelings had risen from 38% to 42%.

It means new generational gaps in attitudes on immigration have emerged in certain countries, particularly in eastern Europe. In Slovenia, millennials are now the most negative of all generations, including baby boomers.

More Slovenian millennials also specifically say they have “very” negative feelings about immigration than baby boomers – 35% versus 31% – suggesting a rise in extreme views among Slovenia’s young.

Millennials in France are also particularly anti-immigration, with half (50%) of that generation telling pollsters they feel negatively, a higher share than gen X and gen z.

But in Poland and Hungary, it is gen Z that are more likely to hold anti-immigration views. More than half (52%) of those born since 1997 in Poland hold negative views about immigration, compared with 42% of millennials and 39% of gen X.

In Hungary, a majority in each generation hold negative feelings about immigration, but gen Z have become relatively more negative than millennials.

Gen Z are also notably more negative about immigration than millennials in Finland, Cyprus and Malta, the Eurobarometer data shows.

This pattern of rising anti-immigration sentiment among the young is a marked contrast to other EU member states, which have seen consistent declines in negative attitudes across generations.

In Germany, Italy, and Spain, the share of respondents saying they feel negatively about immigration consistently falls between generations.

The data comes as EU member states prepare for June’s European parliament elections, in which resurgent far-right parties are expected to make gains.

On 19 May, Europe’s far-right leaders, including France’s Marine Le Pen, Hungary’s Viktor Orbán and Italy’s Giorgia Meloni met in Madrid for a convention organised by Spain’s Vox party, and made calls for their parties to collaborate ahead of the vote.

In a video message, Orbán said it was time “for patriots to occupy Brussels”, adding that those in the Belgian capital were “unleashing massive illegal migration”. Meloni, who also appeared via video, said: “We’re at the eve of decisive elections. It’s time to mobilise, to get out on the streets. It’s time to raise the stakes; it is our duty to fight to the last day.”

A particular campaign issue for the far-right ahead of the elections has been the EU’s contentious asylum and migration pact, recently approved by the European parliament after years of setbacks and stalemates over the deal.

The pact – which establishes border centres to hold people while asylum requests are vetted and speed up any deportations – has been widely seen as an attempt to stave off the far-right capitalising on rising anti-immigration sentiment across Europe. It has been criticised by more than 160 rights organisations, including Amnesty International, Human Rights Watch and the International Rescue Committee.

Yet some on the far-right have already criticised the pact for not being tough enough, as well as rejected new solidarity rules the pact introduces over the relocation of refugees. Hungary and Poland had swiftly said they will not accept relocations after the pact was passed.

Data from Frontex, the EU’s border agency, shows that irregular migration to the EU has risen in the past few years, though is still far below the levels seen during the bloc’s 2015-16 refugee crisis.

In 2023, 385,445 irregular border crossings into the EU were registered through routes like the Mediterranean and the bloc’s eastern borders, an increase on 326,217 registered in 2022 and 199,898 in 2021.

However, 1,882,102 irregular crossings were registered in 2015, at the height of the refugee crisis.