LONDON (Reuters) - Despite her runaway lead in opinion polls, Prime Minister Theresa May said on Tuesday she would fight for every vote in an election she hopes will strengthen her in Brexit talks with the EU and help her prevent the break-up of the United Kingdom.

FILE PHOTO: Britain's Prime Minister Theresa May speaks to the media outside 10 Downing Street, in London, Britain April 18, 2017. REUTERS/Toby Melville/File Photo

In Wales, a largely rural country that has long been a stronghold of her Labour opponents but which voted in favour of Brexit last year, May took aim at opposition parties to press her argument that only she can win a good deal with the European Union.

Her visit is timely, with Labour on the back foot over its Brexit plans and an opinion poll suggesting her Conservatives are on track to win a majority of parliamentary seats in Wales on June 8 - the first time in more than 100 years.

“So my message is very clear - on the 8th of June vote for strong and stable leadership ... Give me a mandate to lead Britain, give me a mandate to speak for Britain, give me a mandate to fight for Britain and give me a mandate to deliver for Britain,” she told supporters in the Welsh town of Bridgend.

“We want to ensure that Britain is a more secure and united nation - that means acting against the extremists who want to divide us but it also means standing up to the separatists who want to break up this precious union of nations.”

It was a clear jibe, not only at Plaid Cymru, the Party of Wales, which supports Welsh independence, but also the Scottish National Party which has stepped up calls for a new referendum on ending Scotland’s centuries-old union with England.

Since being appointed prime minister after Britain voted to leave the EU last June, May has made maintaining the union of England, Scotland, Wales and northern Ireland a top priority.

NO COMPLACENCY

By calling an early vote, three years before it was scheduled, May has caught opposition parties off guard and sent them scrambling to come up with election manifestos.

She is trying to cast the election as a choice between stability under her leadership and chaos under Labour, whose left-wing leader Jeremy Corbyn saw off a party revolt last year but is still struggling to impose his control.

Labour said on Tuesday it wanted to change the tone of the upcoming divorce talks with the EU talks by immediately guaranteeing the rights of millions of EU citizens in Britain if it won the vote.

With national opinion polls giving her a lead of around 20 percentage points over Labour, May looks set to get a large majority in parliament, easing passage of the dozens of laws needed to extract Britain from the EU.

But she may also face election fatigue among an electorate who voted in the EU referendum less than a year ago.

“We must not be complacent and I am not complacent. I am going to be out and about. I’m going to be campaigning and working for every single vote,” she said.

“The choice at this election is very clear choice between that strong and stable leadership under the Conservatives or a weak and unstable coalition of chaos led by Jeremy Corbyn.”