Prime Minister Theresa May wants 'more united Britain'
Theresa May has set out her desire to create a "more united" Britain, in a speech in Cardiff.
The prime minister told the Conservatives' spring conference that Britons are "at heart one people" be they Welsh, English, Scottish or from Northern Ireland.
It follows Nicola Sturgeon's demands for a second independence referendum for Scotland.
Mrs May has already rejected the call from Scotland's first minister.
Scotland voted to remain in the UK in 2014 but the SNP administration in Edinburgh wants a fresh vote as the UK plans to leave the European Union.
Scottish voters opted by a majority to remain in the EU, with England and Wales voting to leave.
Mrs May said on Thursday it was "not the right time" for another independence referendum.
In her conference speech on Friday, the prime minister described her triggering of the Article 50 process for Brexit as one of the "great national moments that define the character of a nation".
With a "road before us" that "may be uncertain at times", the UK could "look forward with optimism and hope, or give in to the politics of fear and despair", she said.
"I choose to believe in Britain and that our best days lie ahead," she said.
The Brexit vote in 2016 was also a vote for changing the way the country works, Mrs May added.
"It means forging a more united nation, as we put the values of fairness, responsibility and citizenship at the heart of everything we do, and we strengthen the bonds of our precious union too," she told the conference.
"It means building a stronger, fairer Britain that our children and grandchildren will be proud to call home."
The union is "more than just a constitutional artefact," she added. "It is a union between all of our citizens, whoever we are and wherever we're from."
The prime minister also promised to take account of competing demands from Wales, Scotland and Northern Ireland as the negotiations begin on leaving the EU, saying: "We are four nations but at heart we are one people."
Opening the conference earlier, Welsh Conservative leader Andrew RT Davies said Labour ministers' plans to scrap the right to buy council homes in Wales would end "one of the greatest aspirational policies this country has ever seen".
Meanwhile education spokesman Darren Millar joked about being dubbed "Millar the Cereal Killer" because of his opposition to free school breakfasts.
The AM for Clwyd South said he had been compared to "Thatcher the so-called Milk Snatcher", before saying he was proud to have been compared to the former prime minister.
Analysis by BBC Wales political editor Nick Servini
This was a Theresa May speech delivered to an audience of the Welsh Tory faithful, but in reality was directed further afield and in particular to a Scottish audience contemplating the prospect of another independence referendum.
The gloves came off as the prime minister visibly became more animated as she called the SNP and Plaid Cymru "obsessives" with tunnel vision.
In fact, Jeremy Corbyn was barely mentioned as nationalist-bashing became the tactic of choice instead from a roll-call of senior party figures.
This conference may have been in Cardiff but there was little to give it a Welsh dynamic, with the focus turned to May's twin battle of Brexit negotiations while trying to hold Britain together.