The Labour party would emerge as the biggest UK force in the European Parliament in British EU elections, according to new projections which show a surge in support for Nigel Farage’s Brexit party.

Labour would return 19 MEPs to Brussels in an EU election which will need to be held next month if Theresa May cannot pass her Brexit deal through parliament before May 22.

The Tories would be in second with 12 seats, and the Brexit party led by Mr Farage, on 10 MEPs, according to the projections. The UK Independence Party would be in fourth place with nine seats.

The projections are the first time the European Parliament has published new MEP seat forecasts to include the UK. Analysts have warned the estimates for the UK are more unpredictable than most as formal campaigning for the elections has yet to begin in Britain.

An internal poll from the EP, carried out on April 10 and seen by the FT, gave Labour a much bigger lead with 28 MEPs.

The UK’s participation in the elections has been opposed by EU leaders like Guy Verhofstadt, the parliament’s Brexit chief, who think it will import the “poison” of the leave campaign into European politics.