Nearly 45 percent of Scots voted on Thursday to abandon the United Kingdom forever, but when the ballots from all 32 voting districts were tallied early Friday, the “no” campaign had won 55.3 percent of the vote, ensuring a more powerful Scotland within Britain.

Image Alex Salmond, Scotland’s first minister, who led the fight for independence. Credit... Matt Cardy/Getty Images

The victory of the “Better Together” camp was ensured late in the campaign when all three main political leaders from Westminster — Mr. Cameron, the Labour Party leader Ed Miliband and the Liberal Democrat Nick Clegg — jointly promised “extensive new powers” to the Scottish Parliament over taxing, spending and welfare, while also pledging to continue the budget allowance Scotland gets, a generous allowance per capita compared with what the rest of Britain receives.

Alex Salmond, Scotland’s first minister, who led the independence fight, called for reconciliation on Friday and then, visibly dejected, announced that he would step down in November. But he made it clear that Scotland would hold the party leaders to their last-minute promises, which Parliament must turn into law, even if the three parties have not quite agreed on the details.

Mr. Cameron was immediately faced with criticism from his own Conservative Party about the blithe manner of the promising and the possible expense. More interesting, perhaps, many legislators said that if Scotland received still more power over its finances, it was time for England to gain more, too. Some even suggested a separate English parliament, like the ones in Scotland, Northern Ireland and Wales.

One of the great anomalies of the British system, as it has developed, is that England is subject to the laws of Parliament in which Scottish, Welsh and Northern Irish legislators vote. But Scotland, Wales and Northern Ireland have their own parliaments that rule, without any English say-so, on many important regional matters.