Mr Salmond, who has until now played down the independence issue in the Scottish Parliament campaign, said separate parliaments north and south of the border were "the only logical path" for both countries. By implication, Wales would also become a sovereign state and the United Kingdom would no longer exist.
In an article in today's Punch magazine, he also suggested that all Scottish MPs should be barred from voting on English affairs in the House of Commons until independence had been secured.
After days of concentrating on tax and health spending, Mr Salmond finally put the state of the Union firmly on the agenda with his claim that English independence was "best for England" as well as the Scots.
"With Scottish independence, England would lose a surly lodger and gain a good neighbour. With Scottish devolution, the UK and England gain a problem, confirming my belief that independence for England is the only logical path... because it is best for England if England takes control and responsibility for its own affairs," he said.
The SNP has long observed a self-imposed rule of refusing to vote on solely English matters in the Commons and a similar edict should apply to all parties, Mr Salmond said.
The independence issue moved centre stage as it emerged that the parties have been warned that they must declare all financial help they receive, including gifts and donations in kind. Professor Anthony King, chairman of an electoral commission set up to oversee the election, has written to the parties, reminding them of their obligation to be open about funding.
Five parties, including the Greens, signed up in February to a voluntary code, which will be used as a test-run for rules due to be implemented before the next general election. They promised to declare national donations of more than pounds 5,000 and local donations of more than pounds 1,000, as well as to bar foreign and anonymous donations.
But although some parties told The Independent they had received non- cash support such as the loan of vehicles, office space and staff, none had passed the information to the commission. Full disclosure could cause problems for the parties because for the first time they are bound by a pounds 1.5m national limit on spending.
So far, Labour has declared pounds 166,000 in donations to its Scottish headquarters since January, pounds 100,000 of which came from the Scottish Trade Union and Labour Party liaison committee. It has not declared any support from its London Millbank offices, although staff have been seconded to help.
The Conservatives have declared pounds 306,600, including pounds 37,500 from headquarters in London; the Liberal Democrats pounds 118,100 including pounds 108,100 from London; and the SNP pounds 130,600, including pounds 15,300 from the actor Sean Connery. The Greens declared just one pounds 10,000 gift.
Donations direct to constituencies amounted to pounds 8,375 for Labour, pounds 12,300 for the SNP and pounds 13,800 for the Tories.