Downing Street officials are preparing for what they expect will be victory for Barack Obama in the US presidential election in November and defeat for Mitt Romney, the Republican challenger, who is a natural Tory ally.

Conservatives made strenuous efforts in the spring to build up their Republican links, including a meeting between the chancellor, George Osborne, and Paul Ryan, now Romney's vice-presidential candidate. But they believe there is a strong personal relationship between Obama and David Cameron that dwarfs any political differences.

Conservatives feel that the Democrats realise the Tories are not on the Tea Party right and that striking similarities exist between their respective deficit-reduction programmes.

Cameron and Obama are entering a critical phase in their relationship, with the UK presidency of the G8 world leaders in 2013 and troop withdrawals from Afghanistan on the horizon.

Obama appears to have gained some political momentum since the party conventions, taking small leads in many swing states, which has prompted some Republican infighting before three critical televised presidential debates.

Conservatives have been taken by the central message of Obama's convention speech, calling on voters to be patient and recognise that the hard path he has chosen is the only one that leads to a better future.

"The truth is it will take more than a few years for us to solve challenges that have built up over decades. It will require common effort, shared responsibility, and bold, persistent experimentation," Obama said.

Conservative strategists believe the British public are receptive to a hard long-term message from government incumbents, and believe Ed Miliband has left himself vulnerable for failing to take tough decisions. Cameron is still beating Miliband in many polls asking who would make a good prime minister.

The strategists take comfort from the fact that although they are often trailing Labour by 10 points, the bulk of Labour's lead has been amassed by Tory voters switching to Ukip, or by former Liberal Democrat voters deserting Nick Clegg's party. They believe few former Tory voters have switched directly to Miliband because of his actions or leadership.

Conservatives believe that voters recognise the UK economy is locked into an ever more competitive global contest for jobs, and will portray Labour's deficit-cutting plans as superficially attractive comfort food that is ultimately damaging. Cameron and Osborne expect the new Conservative chairman, Grant Shapps, to mount an increasingly pointed attack on Ed Balls' spending plans.

Officials expect that the two most challenging political reports facing the government this autumn will be that of the Leveson inquiry into media ethics, and the Office of Budget Responsibility's verdict on the feasibility of the government meeting its long-term debt-reduction plans. Both are expected in November.

Some government officials are taking soundings with newspaper owners about whether they would accept any form of independent regulation with statutory underpinning.

Resistance continues among many proprietors.

One proposal regarded favourably within parts of Downing Street is the regulatory oversight provided by the Advertising Standards Authority – a system described as self-regulation within a co-regulatory framework. The ASA system is underpinned by an enabling statutory instrument, and a formal memorandum of understanding between Ofcom and the ASA.

Cameron, currently on better terms with the right-of-centre press, will have to make a political judgment on how far to press the media. Many in the party believe Leveson has made his task more difficult by allowing the inquiry to roam so widely, including exploring the circumstances of News Corp's bid for BSkyB. Labour has opened a 15-point lead over the Conservatives, according to a Times/Populus poll last night. There was some comfort for the prime minister, however, as the poll showed 60% of respondents wanted Cameron to remain in his post. The poll put Labour on 45%, the Tories on 30%, and the Lib Dems on 10%.