PM kicks off new year with pledge to increase state pension but refuses to commit to keeping raft of benefits for elderly

David Cameron has signalled that he wants to cut taxes for the lowest paid and pledged to increase the state pension but refused to commit to keeping a raft of benefits for the elderly, from free television licences to bus passes.

With just 16 months to go before the next election, the prime minister kicked off the new year on Sunday with a series of hints about the next Conservative election manifesto, mentioning lower taxes, higher pensions, immigration, welfare and education as key areas.

Over the weekend, Cameron had revealed that he would keep the so-called "triple lock" on pensions for the rest of the decade – a pledge to increase it annually by inflation, average earnings or 2.5%, whichever is highest. Speaking on the BBC's Andrew Marr Show, he defended this decision to protect the income of pensioners above other age groups at a time of austerity as "a choice based on values, based on my values".

However, he declined to say whether he would repeat a promise made at the last election to keep a raft of controversial benefits for the elderly – the group most likely to vote. These include free television licences, bus passes and winter fuel allowances.

At the same time, Cameron played down reports that he could order more tax cuts for the wealthiest, saying he wanted to target any extra available money at the lowest paid.

The speculation was prompted by an interview with the Sunday Times, in which the prime minister said cutting the 50p top rate of tax to 45p was an example of the government being prepared to scrap something holding back the economy even if it was politically unpopular. "If people can bring forward arguments about how to maximise the revenue from the top rate of tax, I'm always interested to read them," he added.

On Sunday morning, Cameron did not rule out a cut in the top rate to 40p but suggested this was not a priority.

"We'll set taxes … to raise revenue, not to make a political point. But if I had money in the coffers I would target that money at the lowest paid," he said.

Cameron also said a Conservative victory at the next election was achievable and that he would go "all out" for it even though the party is far behind Labour in the opinion polls.

"We've got 16 months to the next election. This year for me is a year about governing, it's about delivering, it's about putting in place the elements of that long-term plan. I'm content that the public will judge me and the government I run and the party I run in 2015," he said.

Labour said the prime minister's words suggested he was still "paving the way for yet another cut to the top rate of tax, a further tax giveaway for millionaires and the top Tory donors who bankroll Cameron's Conservative party".

Michael Dugher, Labour's shadow minister for the Cabinet Office, added: "Cameron's tetchy interview underlined that he is out of touch with the country and that he has no answers to Britain's cost-of-living crisis."