The Scottish National Party has renewed the call, along with Plaid Cymru, for Tony Blair to be impeached over the war in Iraq.
The SNP says Tony Blair has lost voters' trust over the Iraq war
The SNP made the joint declaration alongside the Welsh nationalist party.
The Conservatives have revealed plans to clamp down on crime as their election campaign theme on Tuesday.
Meanwhile, the Liberal Democrats are concentrating on childcare while the Labour Party looks towards the employment sector.
Campaigning together in Edinburgh, nationalist leaders Alex Salmond and Elfyn Llwyd said they intended to resubmit their motion to impeach the prime minister.
Mr Salmond said: "Tony Blair has lost the trust of the people of Scotland.
"The electoral arithmetic means the Tories can't beat him south of the border, but Scotland will play a pivotal role in delivering the knock-out blow.
"Each and every SNP candidate elected in May will be lined up behind a motion to impeach Tony Blair, so we can hasten his departure as prime minister."
Mr Salmond added: "If the Lib Dems and the Tories are serious about holding the prime minister to account they should back our motion."
Mr Llywd criticised the Lib Dems for failing to back earlier calls to impeach the prime minister and said they stood back as Plaid Cymru members were ejected from the Commons for calling Mr Blair "a liar".
For the Tories, Peter Duncan argued that Conservative plans to end automatic early release for prisoners while increasing police numbers by 1,500 would provide a real boost to law enforcement across Scotland.
"We want to see police officers where they should be - out on the beat deterring and detecting crime instead of sitting behind a desk filling out forms," Mr Duncan said.
"That is what the decent majority of people want to see and it is what will make them feel safe in their own neighbourhoods again.
Peter Duncan: Tories would make prisons "drug-free"
"We will take a zero-tolerance approach to drugs, which scar our communities. Our jails will no longer be places where people can get drugs as easily as they can on the streets.
"We will also make our prisons 'drug-free'."
Scottish Lib Dem leader Jim Wallace highlighted his party's efforts to engage children in mentally and physically challenging activities with a visit to an innovative child care centre.
Mr Wallace said a Lib Dem government would invest about £300m to improve childcare services in Scotland.
The Lib Dems want to scrap the Child Support Agency "because it fails too many families".
Mr Wallace added: "We will provide flexible care in local schools for before and after the school day, giving the opportunity of affordable childcare between 8am and 6pm.
"Taken together, Lib Dems offer a package of investment that will deliver real solutions to the real problems facing families and children."
Scottish Secretary Alistair Darling took Labour's campaign trail to Glasgow and drew attention to the impact of the minimum wage.
He said: "The minimum wage has delivered a pay increase for 140,000 Scots. These people will see their pay rise to £5.05 an hour in October 2005, and £5.35 in October 2006.
"That pay rise will be at risk if the Tories win on 5 May. Only Labour can ensure that work pays."
Elsewhere, the Scottish Greens have urged voters to make nuclear power an election issue and oppose any Labour plans to increase the number of nuclear stations.
Green MSP Chris Ballard said nuclear power had proved to be "a dirty, risky and expensive mistake" which had been illustrated by the Chernobyl disaster in 1986.
Scottish Socialist Party leader Colin Fox has called for the minimum wage to be increased from its present £4.85 an hour to £8.
"Low pay and long hours are Scotland's national disgrace," he said.
"The UK has the longest working hours in Europe and a mountain of personal debt."