The Socialists will improve on their 198 seats, partly because the number of seats will go up from 518 to reflect German unification, and the EPP will decline from 162. But huge uncertainties hang over the result, because of the unpredictability of the British result and the question-marks over the political groupings that parties from France and Italy will join.
Estimates of the number of British Conservatives returning to Strasbourg range between six and 20, for Labour between 50 and 66 and for the Liberal Democrats between five and 15.
This could make some important differences to the final shape- up of the party blocs and the British results will be watched carefully on Sunday night.
Britain's first-past-the-post system (which does not operate in Northern Ireland) is likely to cause controversy if the results lead to a Tory wipe-out.
The EU is committed to a single system for electing MEPs and only Britain uses a system that allows such big swings.
But even greater doubt is cast on the parliament's final make-up by the uncertainty over who joins up with whom. The parties in the ruling Italian coalition have yet to decide on their blocks, and the French Gaullist RPR are supposed to join the EPP but may not. If both joined, the final score for them could be between 170 and 180, depending on how many Conservatives are returned to Strasbourg. If neither join, and the Tories are wiped out, it could be reduced to as low as 130.
The Socialists will have 145 without the British Labour members. That could go up to 210 with a Labour landslide. In France, Bernard Tapie, the former football boss and millionaire, heads a list that is likely to gain 10 seats and will probably join the Socialists. Jean-Pierre Chevenement, a maverick Socialist, may win three seats and it is uncertain where he will end up. Assuming Labour wins about 55 seats, that leaves the Socialists with 210 - about the same percentage of seats they have now.
The Liberal Democrat and Reformist Group, the third largest, could increase from 45 seats to 55 assuming that the British Liberal Democrats win 10 seats. The Greens look set to go up marginally from 27 to 29.
The far right in Europe may have a poor election, with the French National Front and the German Republicans both expected to decline. The Technical group of the European Right could shrink below the level required for a single group, if the Italian neo- Fascists do not join up, forcing it to bow out. The rules of the European Parliament say that to become a political group requires 13 members from four countries or 26 from one country.
Equally, if the French Gaullists join the EPP, the European Democratic Alliance, of which some are members, may disintegrate. This bloc includes members of Fianna Fail, who may have to seek a new home - perhaps with the Rainbow group, which hosts diverse interests. The future of the Rainbow group - which groups regionalists from around the EU, including the Scottish Nationalists - depends crucially on what happens to the regionalists from Spain and Italy, which could see it grow from 14 to as many as 25.Reuse content