Cameron, Miliband and Clegg release Christmas messages
David Cameron has stressed his pride in the UK's "Christian values" in his annual Christmas message.
The prime minister said "giving, sharing and taking care of others" at home and around the world was something the UK could be depended upon for.
Deputy PM Nick Clegg said the values of love, hope and charity expressed in the Christmas story were "universal".
Labour's Ed Miliband urged voters to choose "generosity and inclusion" in the looming election battle next year.
In his seasonal message, Mr Cameron - the only one of the three leaders to describe himself as Christian - praised the work of the military, aid workers and medical volunteers abroad as well as emergency service workers in the UK.
"Among the joyous celebrations we will reflect on those very Christian values of giving, sharing and taking care of others," the Conservative leader said.
"This Christmas I think we can be very proud as a country at how we honour these values through helping those in need at home and around the world.
"So this Christmas, as we celebrate the birth of Christ with friends, families and neighbours, let us think about those in need at home and overseas, and of those extraordinary professionals and volunteers who help them."
The message from Mr Miliband - who has said he does "not believe in God personally" - recalled the famous truce observed by soldiers in the trenches on Christmas Day 1914.
"One hundred years ago soldiers on the Western Front stopped their hostilities to cross no man's land, to shake hands and - famously - to play football," he said.
"In the midst of a tragic conflict the generosity, hope and sense of human solidarity that is characteristic of the Christian faith and culture came to the fore. What an extraordinary and unexpected event.
"We need the same sense of compassion in the face of the suffering and hatred that afflicts parts of our world. I am proud that the Labour movement has such deep roots in the Christian tradition of social activism and solidarity in the United Kingdom."
Turning his thoughts to 2015 - in which the general election is scheduled to take place on 7 May - he added: "Our country faces a choice next year. Let's choose generosity and inclusion."
Liberal Democrat leader Nick Clegg also based his message on the Christmas truce, saying it had offered soldiers on both sides a "moment's respite" from the violent conflict in which they were engaged.
"This Christmas and beyond, we can each do our bit to help secure the fairer, more peaceful world that the soldiers in 1914 longed for and our children deserve: reaching out to those people - wherever they may be - who feel isolated, who are caught up in conflict or who need our help," he said.
Mr Clegg, who said in 2007 that he was not an "active believer", said that the "heart" of the Christmas festivities is "the birth of Jesus Christ, a time of joy and celebration for Christians around the world".
The Christian values of love, charity and hope expressed through the story are "universal, speaking to and uniting people of all faiths and none", he added.