Jack Straw yesterday warned Scottish voters against using the May 3 poll to give the government a bloody nose because they would "rue the day" Alex Salmond got his hands on power in Scotland.

At his weekly briefing with Westminster reporters, the leader of the Commons - and Gordon Brown's campaign manager for the Labour leadership - emphasised how the government's record of economic and social progress in Scotland was "incontravertible" and flagged up how the polls in Scotland showed most people were "wholly opposed" to the SNP's central policy of independence.

However, he pointed out how people sometimes used mid-term elections to make a mid-term protest and hoped it would not have an effect. "Sadly, people have done that sometimes at local elections and then ended up with an incompetent Liberal Democrat council, to give an example, and rue the day.

"They would rue the day even more if they ended up with Alex Salmond running everything."

Asked that if Labour's record of success was so incontravertible why it was doing so badly in the polls, Mr Straw replied: "Let us wait for the real poll on May 3."

Mr Straw also came to the Prime Minister's defence in the Commons yesterday when he dismissed a demand for him to announce his resignation as Prime Minister to MPs first, rather than the Queen.

Senior Tory Sir George Young had observed: "The ministerial code says that when Parliament is in session the most important government announcements should be made in the first instance to the House.

Mr Straw advised: "The appointment of Prime Ministers is a matter for Her Majesty - it's under her prerogative powers. It is not therefore a matter for this House."

Today Tony Blair will rally Labour Party activists with a damning indictment of David Cameron's leadership of the Tory Party. Although opinion polls show an upturn in Tory fortunes Mr Blair will argue that 18 months into the new Conservative leadership it is now obvious that the Tories are beatable at the next General Election.

Speaking in his Sedgefield constituency, only 12 days before elections for local authorities, the Scottish Parliament and the Welsh Assembly, Mr Blair will say that Mr Cameron has learned the tactics of opposition but has not found a strategy for government. He will also say that the Conservative Party is making strategic misjudgements.

Mr Blair is trying to minimise Tory advances in local authority elections in England and Wales, where Mr Cameron is anticipating a revival in the party's fortunes.

Hazel Blears, the Labour party chair, last night published a mid-term report underpinning the Prime Minister's criticism of Mr Cameron. Citing a list of failed Tory policies, Ms Blears said: "The record of David Cameron's leadership is clear. Whether on policy or on reform of his party, he has failed to change the Tories in the way he has promised, and remains, in his own words, "Conservative to the core'."