Graham Fraser
BBC Scotland

That is it for tonight's debate. You can read a report on it and watch video highlights on the BBC Scotland news website.

Also, you can watch the whole programme again on the BBC iPlayer soon.

Jim Murphy said governments need to invest much more in social housing.

Ms Sturgeon, responding to criticism for scrapping the right to buy scheme, said the policy "had had its day".

Ruth Davidson criticises the SNP and Nicola Sturgeon for scrapping the help to buy scheme in housing.

What did the Scottish Conservative manifesto say on housing?

• Extend the "Right to Buy" to 1.3m housing association homes in England

• 200,000 homes built for first-time buyers aged under 40, at 20% discount

• New Help to Buy ISA's for first-time buyers to help them get a deposit for a house

• Create a £1bn brownfield regeneration fund to unlock sites for 400,000 homes

Willie Rennie agreed with Nicola Sturgeon, and said it is important to build hundreds of thousands of homes across the United Kingdom.

He added that by creating jobs, young people will be able to buy their own homes.

What did the Scottish Lib Dem manifesto say on housing?

• Increase house building to 300,000 a year

• Set in motion at least 10 new Garden Cities

• 30,000 Rent to Own homes a year by 2020

• Ban landlords from letting out poorly insulated homes

Jim Murphy said 95% of all money spent on housing in Scotland is spent on benefits.

He said it important to regulate rents in the private sector so landlords can't rip young people off.

What did the Scottish Labour manifesto say on housing?

• Full devolution of Housing Benefit

• Build 20,000 new homes a year in Scotland by 2020

• Abolish the "bedroom tax"

Nicola Sturgeon is the first leader to speak about the issue of housing.

She says the SNP, in the Scottish Parliament, want to build 30,000 homes in the lifetime of this parliament.

What did the SNP manifesto say on housing?

• Immediate abolition of "bedroom tax"

• Back investment to see 100,000 affordable homes built throughout the UK

• Continue support for Help to Buy and shared equity schemes

• Housing benefit should not be restricted for 18 to 21 year olds

On the issue of tactical voting, Ms Davidson said she doesn't believe with it "in principle".

Mr Murphy, meanwhile, said he believes in the first-past-the-post system.

Ms Sturgeon said the SNP was in favour of proportional representation, and adds the House of Lords should be abolished.

Mr Rennie said the Liberal Democrats believes every vote should count.

He said that proportional representation would mean you could vote in what you believe in, and not vote in all different directions.

He calls the current voting system is "corrupt".

Niall Rolland tweets, external: Great question about need to move to a fairer electoral system in #leadersdebate

Ms Davidson said proportional representation would be "great for the Tories".

She said at the last general election in Scotland, the Conservatives got one in six votes but one in 60 seats.

Jim Murphy says there should be a moratorium on another independence referendum, ruling it out for at least five years.

Ms Sturgeon said the only parties talking about the referendum are the other parties.

Ms Davidson adds that the SNP are not representative of all the people of Scotland.

Galesa tweets, external: A little less shouting please...#leadersdebate

Paul Hutcheon tweets, external: Nicola Sturgeon on which issues would produce a 2nd indyref: 'I'm not going to produce a list.' #leadersdebate

Ms Davidson said the Conservatives have taken a stance that it would do no deals with any of the nationalist parties from across the United Kingdom.

Ruth Davidson said the "deal-by-deal" vote Labour and the SNP would do is the sort of politics that voters don't want.