David Cameron pledges 2016 'game-changer' in new year's message
David Cameron says 2016 will be a "game-changer" for the UK, pledging reforms to home ownership and a crackdown on extremism.
In a new year message, the PM said he was determined to "secure our future" with the EU referendum, which could be held this year.
Jeremy Corbyn said 2016 would mark the "start of the journey" towards a Labour government.
In his new year's message, the Labour leader pledged to fight austerity.
Leaders of other political parties have also issued new year messages. Scotland's First Minister Nicola Sturgeon said 2016 would be "a year of optimism", while Nigel Farage tweeted: "Let's make 2016 the year that the UK votes to leave the European Union."
Mr Corbyn, who has faced criticism from some MPs since winning the leadership election in September, said he was elected "on a mandate for change".
With his first major electoral tests looming in May's local and devolved administration elections, he said his party would "offer a real alternative: a politics that gives people a say in the decisions that affect them, and an economy based on long-term investment, instead of self-defeating austerity".
The Labour leader said he would tackle David Cameron's government "much more" on cuts to local councils and lack of investment.
Mr Cameron said some people choose to "shout into megaphones, wave banners and sign petitions".
He added: "But we're the ones who are able to make the arguments and take the difficult decisions in order to defeat these social scourges and deliver real security. So while others are on protest marches, we remain on the long walk to a greater Britain."
He promised "real social renewal" in tackling poverty and improving social mobility, repeated pledges on house-building and said the government would "respond with vigour" to an extremism review later in the year.
Tim Farron used his first New Year's message as Liberal Democrat leader to criticise Labour and the Tories for being divided.
He criticised government cuts to Universal Credit and policing and said more should be done to support refugees fleeing Syria.
Nicola Sturgeon said she wanted 2016 to be "a year of optimism and ambition" with supporting enterprise and innovation in public services her priority, while leaders of Scottish Labour and the Scottish Green Party set their sights on May's Holyrood elections.
Leaders of Wales' four political parties also looked ahead to the 2016 elections, with Plaid Cymru's Leanne Wood pledging to travel the "length and breadth" of the country and making the case for her party.
Green Party leader Natalie Bennett said the membership of her party had more than trebled in 2015, and she was determined to turn the "Green surge into Green votes" this year.