The postponement affected some 37,000 ‍registered voters, or about 0.3 per cent of the total, and is unlikely to influence the overall result.

With ‍nearly 70 per cent of votes counted, 63-year-old Seguro had 64 per cent.

Ventura trailed behind at 36 per cent, still likely to secure a much stronger result than the 22.8 per cent ‌his anti-immigration Chega party achieved in last year’s general election. Ballots in large cities such as Lisbon ‍and Porto are counted towards the end.

Two exit polls placed Seguro in the 67 per cent to 73 per cent range and Ventura at 27 per cent to 33 per cent.