UK Prime Minister Gordon Brown will today (19 February) pledge to keep Britain "in Europe's mainstream" if re-elected this year, criticising the more Eurosceptic stance of a Conservative opposition expected to win power come May.
Brown, due to address left-wing European politicians in London, will accuse the Conservatives of "narrow nationalism" as he tries to build on improving opinion poll ratings that have made a Conservative majority in parliament look less certain.
"As long as I remain prime minister, Britain will stay firmly in Europe's mainstream, never in its backwaters, and we will resist the attempts of the Conservatives to pull Britain into isolation," Brown will say, according to extracts of his speech released in advance.
Most commentators think Labour is likely to lose the election, expected on 6 May, bringing an end to 13 years of centre-left government and opening up the possibility of a changed relationship between Britain and the European Union.
Brown says he thinks he can win but polls suggest the best he can hope for is to limit the Conservatives to a result short of an overall majority, and then try to form a coalition with the centre-left Liberal Democrats, Britain's third party.
While Europe has never been top of Brown's agenda – he often missed EU meetings during a decade in charge of Britain's finance ministry – a Conservative government is likely to be less willing to take orders from Brussels.
Last year, the Conservatives pulled out of the European Parliament's main centre-right bloc, the European People's Party, to set up an anti-federalist grouping.
The party was against the adoption of the Lisbon Treaty and has pledged to do more to protect Britain's legislative sovereignty if elected. That approach has raised some eyebrows on the continent and beyond.
The issue of Europe could also prove a thorn in the side for Conservative leader David Cameron at home as it has done for several of his predecessors, given internal divisions over just how Eurosceptic the party should be.
Many think Cameron has been too soft, pointing to European elections last year in which the anti-EU UK Independence Party won more votes than Labour. For Brown, attacking the Conservatives over Europe is one of the few options he has left for winning back public support following the worst recession since the Second World War.
"We [the centre-left] are, of course, the true internationalists – the people who know we are stronger together than we ever could be apart," the Labour leader will say.
(EURACTIV with Reuters.)