Ruth Davidson has launched the Scottish Tories' programme for a "stronger opposition" at Holyrood with a pledge that her party will staunchly oppose a second vote on independence.

The Scottish Conservative leader insisted there are no "so-called indyref triggers that justify another referendum", as her party's manifesto vowed to support a "fresh positive drive to promote the Union".

The manifesto, published in the run up to the Scottish Parliament election, said the Conservatives would back the creation of "a new UK-wide effort to promote the strengths and values of the Union".

But she vowed this would not see the return of "Project Fear", as the campaign to keep Scotland in the UK in 2014 was dubbed.

The Tories are hoping to secure their best ever Holyrood election result on May 5, with Ms Davidson setting her sights on becoming the next leader of the opposition in the Scottish Parliament.

Read more: Ruth Davidson says the Tories are snapping at Labour's heels for second place in Holyrood election

Polls show Nicola Sturgeon's SNP are on course for another majority, and Ms Davidson conceded: "Folk aren't daft. They know the likelihood of me moving into Bute House (the First Minister's official residence) is next to nil."

Instead, she said: "I seek to lead a strong opposition to the SNP. And this manifesto today sets out how.

"So it isn't a programme for government - it is a programme for that strong opposition. It sets out how we intend to challenge the SNP in the event that they are returned for a third term in office."

Ms Davidson said the Tories in opposition would set up their own panel of economic advisers to help them "provide a counterweight" to plans to increase income tax for Scots.

They would challenge the government to scrap the named-person scheme, and instead set up a new Crisis Family Fund in its place to provide early intervention to "troubled families".

Read more: Ruth Davidson says the SNP's tax plan is 'realistic and responsible'

Conservatives would also demand spending on the NHS rises by at least 2% a year, and press for an extra £300 million to be spent improving mental health services over the course of the next parliament.

The manifesto calls for 100,000 new homes to be built over the next five years, and for £1 billion to be spent improving energy efficiency so no-one has to live in a cold home.

But the manifesto stresses: "To get better government, Scotland needs a strong opposition which will stand up against the SNP's drive for independence."

Speaking at the launch in Glasgow, Ms Davidson said: "Firstly we do not believe that there are any so-called 'indyref triggers' that justify another referendum - and that includes any hypothetical scenario resulting from June's EU decision.

"And secondly, as our manifesto makes clear, we need to make the counter case to the SNP."

Read more: Ruth Davidson rules out Tory support for SNP in Holyrood

While she said this "is not something that any party alone should undertake", she added it "is a task that as the principle opposition party we should be determined to shoulder".

With First Minister Ms Sturgeon having already announced the SNP will stage a fresh bid to convince voters of the case for independence, Ms Davidson argued it is important that "the clear pro-UK case is made as well".

She said: "Too often over recent years our case for the Union has simply been a matter of picking at the flaws of independence, of dissecting the numbers, rubbishing the projections or disputing proposals. Easy - but ultimately not enough.

"Too often we have failed to make the case for why our family of nations works.

"And the legacy from the referendum is that we on the pro-UK side have allowed 'No thanks' to be seen as a constant negative.

"If we are to counter the SNP's misinformation, this must change. The case for independence is dead. The case for the Union must now be made.

"And our aim must be clear - we want to listen, to learn and to convince people who voted to leave the United Kingdom that a Scotland within it can meet their aspirations and ambitions."

Ms Davidson continued: "We can't win a continuing case for the United Kingdom by only pointing to the negatives of independence or showing where the white paper didn't work.

"What I'm saying is no more Project Fear - this is about a positive case to say 'here are all of the things where we work well and work better with our colleagues just over the border'."

With the Scottish Government having "already pledged it is going to have an all-out campaign" on independence, Ms Davidson argued the issue is "not really an option that we can shirk".

She added: "For me it's not necessarily creating a huge new campaign vehicle but it's about making sure those of us who do believe that we are better, stronger, better able to cope with working together in the world to make that case in a positive manner."

The Tory leader also stressed the importance of having a strong opposition at Holyrood that "properly scrutinises and challenges" ministers and their legislation, saying without this "you get lazy government and bad law".

She said Labour are "heading for their worst ever Holyrood result", and she urged voters to back a change in the main party of opposition.

"I think people in Scotland have a pretty strong sense of fair play," Ms Davidson said.

"So I say the Labour Party has had nine years, six leaders and no success in holding the SNP to account. It's time for somebody else to get a go."

But both the SNP and Labour hit out at the Conservatives over plans to scrap free university education and reintroduce prescription fees.

SNP campaign director John Swinney said: "Ruth Davidson admits her manifesto isn't a programme for government and that her party have no intention of setting out a detailed plan on how they would run Scotland.

"That is irresponsible and disrespectful to voters, who deserve better from the Tories than a long list of things they are against and virtually nothing about what they are for or what they would do given the chance."

He added: "Their only policies of note are their deeply unpopular, regressive plans to bring back university tuition fees of £6,000 and to slap a tax on the sick by bringing back prescription charges.

"Those stealth taxes on some of the poorest people in Scotland completely undermine the Tories' claims to be a tax-cutting party.

"As for Scotland's future, no single party or politician - and certainly not Ruth Davidson - has the right to dictate what that should be. Only the people of Scotland can and will determine this nation's future constitutional path."

Labour equalities spokesman Neil Findlay also called on the Conservatives to "spell out the cost of their plan for secret taxes on the sick and on students".

He said: "Instead of setting out a vision for the NHS, Ruth Davidson wants to introduce a tax on the sick by reintroducing prescription charges.

"The Tories think education in Scotland is a privilege, not a right, and want to scare off students from poorer backgrounds by reintroducing tuition fees worth thousands of pounds.

"On tax, the defining issue of this election, Ruth Davidson has nothing to say. A vote for the Tories in May is a vote to endorse (Prime Minister) David Cameron and (Chancellor) George Osborne's tax policies. They won't do a thing to stop hundreds of millions of pounds of cuts to schools and public services.

"Ruth Davidson wants to take Scotland back to the arguments of the past because she has nothing to say about using the powers to stop the cuts."

Scottish Liberal Democrat leader Willie Rennie said: "The biggest financial investment that the Scottish Conservatives want to make over the next five years is to cut tax for the highest earners. They are doing this simply to match George Osborne.

"The Scottish Conservatives are carbon copies of George Osborne.

"Scotland deserves better. The Conservative tax cuts for the rich and stealth tax increases for everyone else are unfair to people in Scotland."

Scottish Green co-convener Patrick Harvie said: "The Scottish Greens have been campaigning on fuel poverty and energy efficiency for years, to the sound of silence from the Tory benches. Ruth Davidson's warm homes pledge is a pretty shameless example of political opportunism.

"In government, her party's unprecedented attacks on energy efficiency initiatives and the renewables sector show their true colours. The Tories' unconditional support for fracking and a fossil fuel economy, and their record of forcing more households into fuel poverty, deserves the contempt of the electorate."