Twenty-two per cent of those aged between 16 and 29-years-old said they identified as Christian, while 70 per cent described themselves as non-religious.
Only four countries - Czech Republic (nine-per-cent), Sweden (18-per-cent), Estonia (19-per-cent) and the Netherlands (19-percent) - were found to have fewer Christians, as a proportion of the wider young adult population.
Graham Nicholls, leader of the Affinity network of evangelical churches in the UK and Ireland told Premier the figures represent the knock-on effect of a spiritual decline among preceding generations.
European countries ranked by proportion of young adults who say they are Christians
Czech Republic 9%
Sweden 18%
Estonia 19%
The Netherlands 19%
United Kingdom 22%
Belgium 25%
France 25%
Hungary 33%
Denmark 34%
Norway 36%
Finland 37%
Spain 40%
Russia 41%
Switzerland 44%
Germany 47%
Austria 52%
Portugal 57%
Ireland 59%
Slovenia 59%
Lithuania 74%
Poland 83%
Source: The 'Europe's Young Adults and Religion' report
He said: "If there's a decline in belief in Christianity and preaching of the Gospel, you get the next generation who don't really believe it anymore but are practising.
"And, then you get the next generation who neither belief or practise it and are willing to say that."
In contrast, 83-per-cent and 74-per-cent of young adults in Poland and Lithuania respectively identified as Christian, as did 59-per cent of those in Ireland and Slovenia.
Author of the 'Europe's Young Adults and Religion' report, Prof Stephen Bullivant from St Mary's University in Twickenham described the differences in religiosity "genuinely remarkable".
Prof Bullivant said: "The differences in the religiousness - or, as dominates in many countries, non-religiousness - of 16-29 year-olds in our sample of European countries is genuinely remarkable.
"There are, moreover, some genuine surprises in the data.
"For example, Ireland's young adults are - contrary to recent reports - still remarkably religious, at least by the standards of other highly developed European nations.
"Meanwhile, countries that had, until quite recently, traditionally strong religious cultures - Lithuania, Belgium, Netherlands, Austria - look to be in serious trouble, in terms of the coming generations."
Conducted by St Mary's University and the Institut Catholique de Paris (ICP), the research analysed data recently gathered from 22 European nations via the European Social Survey.
Academics concluded then ten-per-cent and seven-per-cent of young adults in the UK consider themselves Catholic and Anglican respectively, while six-per-cent identify as Muslim.
Click here to listen to Premier's Alex Williams speaking with Graham Nicholls at Affinity:
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