Ukip's manifesto offers 'serious, fully-costed policies' for people who 'believe in Britain', Nigel Farage said as he prepared to launch the party's detailed programme.

An in/out referendum on Britain's membership of the European Union 'as soon as possible', a five-year ban on unskilled migrants coming in to the UK and a points-based system for others are among its key pledges.

But with the party keen to broaden its appeal and build on a surge which saw it win last year's European elections, it offers boosts for first-time buyers, military veterans, small businesses and hospital patients.

Under Ukip plans, the NHS would receive an extra £12 billion across the five years of the next Parliament with another £5.2 billion being added to social care budgets.

And - in contrast to the Conservatives - defence spending would be kept at or above the Nato target of 2% of GDP, paid for in part by slashing the foreign aid budget by £9 billion a year.

Tories said that cash - as well as proposed savings from leaving the EU, reducing funding to Scotland and scrapping the HS2 high-speed rail project - had been spent several times over, leaving a £37 billion 'black hole'.

But Mr Farage - who famously dismissed his party's 2010 manifesto as '486 pages of drivel' - said the new document showed there was 'real change on the horizon' in British politics for the first time in a century.

Despite a decline over recent weeks, Ukip remains comfortably the third most popular party in opinion polls and is looking to hold a pivotal role in any coalition negotiations by increasing its current tally of two MPs.

'In our manifesto, launched today, you will find serious, fully-costed policies that reflect what Ukip is all about: believing in our country,' said Mr Farage - who has said bringing forward the Tories' proposed 2017 EU referendum would be a key demand in any post-election deal.

'On the major issues of the day - immigration, the economy, our health service and living standards - the establishment parties have repeatedly and knowingly raised the expectations of the public, only to let us down, time and time again.

'In many ways, this is where Ukip came from: a feeling that successive governments were no longer representing the will of the British people.

'Now, at last, there is something to vote for, if you believe in Britain.

'If you believe that we are big enough to make our own laws, in our own parliament; if you believe we should have the sovereign right to control our own borders; if you believe that we should be fiscally responsible, and stop adding to our national debts and expecting our children and grandchildren to pay the bill, then we are the party for you.'

Among other pledges in the manifesto will be:

:: Create 6,000 police, prison and border jobs for people leaving the armed forces and build a dedicated military hospital;

:: Waive stamp duty on new homes worth up to £250,000 built on brownfield sites;

:: Cut business rates for small businesses;

:: Abolish hospital parking charges.

:: End sham marriages by restoring the primary purpose rule.

A Conservative spokesman said: 'Ukip saying their numbers add up is like Labour saying they're not going to raise your taxes.

'We all know that Nigel Farage doesn't have a credible plan for Britain - he just makes it up as he goes along.

'All voting Ukip will do is put Ed Miliband in Downing Street by the back door - meaning more borrowing, more taxes, more benefits, weaker defences and more debt than our children could ever hope to repay.'