Conservative ministers are preparing to rebuild bridges with Liberal Democrat colleagues after a bruising referendum campaign which has threatened to strain tensions within the coalition to breaking point.
As voters turned out in polling stations across the country, the Conservative Leader of the Commons Sir George Young insisted the divisions which had opened up between the two parties would soon heal.
Deputy Prime Minister Nick Clegg's Lib Dems looked set to be the big losers in what is the biggest electoral test for the coalition since it was formed a year ago.
The final opinion polls suggested the referendum on adopting the alternative vote (AV) system for Westminster elections - which the Lib Dems strongly support - was heading for an overwhelming defeat for the Yes campaign when the result is announced late tomorrow.
At the same time the Lib Dems were braced for heavy losses across a swathe of elections for English local authorities and the devolved legislatures for Scotland, Wales and Northern Ireland.
Voting in his Sheffield constituency, Mr Clegg appeared to acknowledge that his party looked set to pay a price for supporting unpopular coalition cuts.
"Lots of people have got, obviously, questions and some people have got objections to what the Government is having to do," he said.
"But I think most people - the vast majority of people - accept that we're having to do a difficult job in difficult circumstances and that we're trying do it as fairly and compassionately and responsibly as possible."
With the Labour Party divided over electoral reform, there were already signs that Mr Clegg was being lined up as the scapegoat for the failure of the Yes to AV campaign.
In the Commons, Labour MPs mocked the Lib Dem leader, suggesting the Yes campaign had suffered from a "dead Clegg bounce" as a result of his unpopularity.
The shadow leader of the House, Hilary Benn, said there had been a "breakdown of collective Cabinet responsibility" in the coalition after Lib Dem Energy Secretary Chris Huhne angrily confronted David Cameron over the tactics of the Conservative-funded No campaign.
"Here we have a Cabinet minister openly criticising the man who appointed him and it appears that the occupant of No 10 is completely powerless to do anything about it," he said.
"As we approach the first anniversary of this coalition, isn't the truth that it is already beginning to fray at the edges as both parties realise that a marriage of convenience is no substitute for voting for what you believe in?"
Mr Huhne's outburst at Tuesday's weekly Cabinet meeting brought to a head weeks of simmering anger among Lib Dems as it became clear that the referendum was heading for a No vote.
Many in the party believe Mr Cameron broke a private assurance that he would not campaign strongly for a No vote.
There was also deep anger at the way the No campaign - which is heavily funded by Conservative backers - personally targeted Mr Clegg for taking what they said were difficult decisions in the interests of the coalition.
In the Commons, Sir George Young acknowledged that there were "tensions" between the coalition partners, but insisted that they were nothing like as bad as those which racked Labour during the Blair-Brown years.
"The truth is that the tensions between the one party opposite are much more damaging than the understandable tensions between two parties during a referendum campaign and local elections," he said.
"But from next week we will be back in business, working together in the national interest, to get the economy back on its feet. Our divisions will heal but theirs never will."
The referendum and the various elections also represent an important test for both Mr Cameron and the Labour leader, Ed Miliband.
Although he supported AV, despite the opposition of most Labour MPs, Mr Miliband is unlikely to face serious consequences if, as expected, there is a No vote.
He does however need to show that he can win back council seats from the Tories and Lib Dems, particularly in areas like the South East where Labour suffered heavy losses in the general election.
However his night could be marred by events in Scotland where First Minister Alex Salmond and the SNP appear to be heading for a second term in charge at Holyrood.
While Mr Cameron was braced for the loss of Conservative councillors, there will be a sigh of relief in No 10 if the referendum does indeed end in a No victory.
The Prime Minister is well aware that he could face real trouble from Conservative backbenchers - who are overwhelmingly opposed to change - if he was obliged to legislate to introduce AV following a Yes vote.