Welsh Secretary Cheryl Gillan: Biggest challenge of all to keep UK together
Welsh Secretary Cheryl Gillan has described the battle to keep the United Kingdom together as "the biggest challenge of all".
She told a party rally the Union had provided "stability and security and proved that we are stronger together than we are apart".
A referendum on Scottish independence is planned for 2014.
The rally at St Asaph, Denbighshire, was held ahead of local elections on 3 May.
The event replaced a Welsh Conservative annual conference due to take place in Llandudno last month, but which was cancelled due to lack of funding.
Mrs Gillan warned that the interests of Wales were best served "in the Union, not on its fringes".
Criticising Plaid Cymru's independence aims under its new leader, Leanne Wood, Mrs Gillan said Wales would be "isolated from the rest of the United Kingdom" if Plaid achieved its goals.
"I hope that Plaid voters will see in Welsh Conservatives a great alternative," she said.
"It is inter-dependence, not independence, that we want.
"Conservatives will back our Union through thick and thin".
She said the Conservative-Liberal Democrat UK government was "investing in the tools we need in Wales to move forward".
"For business, super-fast broadband, mobile phone signal improvements, rail electrification, finance for the enterprise zones, lower business taxes and at the same time taking 95,000 people out of paying any income tax whatsoever and reducing the taxes of over 1.1m people in Wales."
Referring to the Silk Commission, which was established by the UK government and currently considering whether the Welsh government should be given taxation and borrowing powers, Mrs Gillan said the Labour Party was right to believe ministers had an "ulterior motive".
She said the intention was to make the Welsh government "more accountable for the money it spends".
"And I want to make sure the decisions on expenditure are fair to taxpayers across the United Kingdom," she said.
Mrs Gillan attacked the record of the Welsh Labour government on school literacy levels, education spending, child poverty and hospital waiting times.
She said she had been "underwhelmed" by Labour's legislative programme for Wales and regarded the rival party's vision as "uninspiring and complacent".
But she said that the UK and Welsh governments must "work together, not against each other" in the national interest.
Mrs Gillan said more voters backing Conservative local election candidates in May would mean more power would be "put back into the hands of communities across Wales".
She added that the party needed to control more councils and to have more councillors elected to protect services, cut waste and deliver value for money with "greater transparency, so the public can see how their money is being spent".