An independent report has predicted that the centre-right will retain the largest share of European parliament seats after June's elections.

The study, by Professor Simon Hix of the London School of Economics and Dr Michael Marsh Trinity College in Dublin, concludes that enlargement will have a relatively minor impact on the distribution of seats in the parliament.

As the institution expands to accommodate new members – up from 622 seats to 732 – the centre-right group is forecast to swell from 231 to 285 MEPs, a slight gain from 37 to 39 per cent.

The socialists are expected to experience a similar waxing in popularity, increasing their share of seats from 27 to 29.6 per cent with 217 MEPs in the new-look parliament.