However, despite being ahead of Europe's Socialist grouping in the polls, the EPP is unlikely to return enough MEPs to command an overall majority in the newly constituted assembly.
The final election prediction released on Tuesday by PollWatch, 2014 - a VoteWatch initiative partly funded by the European parliament - suggests that there will be a "dramatic polarisation" of the new parliament, with a significant increase in MEPs on the right and left of the parliament's two main political groupings.
The results, say the researchers involved - Simon Hix and Kevin Cunningham - show that there will be a, "squeezed middle, with the three largest groups, the EPP, S&D and the Liberal ALDE alliance, down from 72 per cent of MEPs to only 65 per cent".
This, say the researchers, "will force the EPP and S&D to work together to get anything done, since neither an EPP-led coalition without the Socialists nor a Socialist-led coalition without the EPP is likely to command a majority".
The VoteWatch team expect the EPP to return with 40 seats fewer than the last election, with 217 seats (29 per cent), 16 seats ahead of the Socialists and Democrats with 201 seats, (27 per cent).
However, the researchers also highlight that, "taking into account the margins of error in the latest polls, and on the basis of 1000 simulations of what might happen, there still remains a 15 per cent probability that the S&D group will be larger than the EPP".
They also highlight that their predictions, "do not take account of potential party switches between groups or of which groups the currently non-attached parties will eventually join – in particular where the 18-20 MEPs from Italy’s Five Star Movement will sit."
With the group affiliations of many of the smaller political parties still uncertain, speculation on the final make-up of the parliament is rife, however the VoteWatch team say that they expect a new grouping, the European Alliance for Freedom (EAF) to be formed by right-wing parties such as Marine Le Pen's France's Front National and Geert Wilders Dutch PVV.