By Nick Assinder
Political correspondent, BBC News website
Tory leader David Cameron has returned from his summer break with one overriding objective - to finish off Gordon Brown's political honeymoon and re-instil a sense of optimism into his party.
After a difficult few weeks for the opposition, sparked by Mr Brown's succession and subsequent good poll performance, Mr Cameron knows he needs to get back onto the offensive or face fresh panic in Tory ranks and even rumblings over his leadership.
Mr Cameron is putting law and order at centre of programme
He left Westminster for his summer holidays with Mr Brown enjoying an expected "bounce" in the polls and a general view he had not put a foot wrong.
The prime minister was setting the political agenda, closing off areas of potential policy advantage to the Tories and even giving the first glimpse of his planned programme of legislation with the first pre-Queen's speech statement.
The tide appeared to be running in Mr Brown's favour and there was even talk of a snap autumn election.
The Tory leader, on the other hand, had suffered significant setbacks with the internal row over the future of grammar schools, a brace of by-election disappointments and the bad timing of his trip to Rwanda while his constituency was flooded.
And there was a sense of panic in Tory ranks at Mr Brown's apparent popularity and Mr Cameron's inability to wipe the new-found smile off the prime minister's face.
The question now, then, is whether a few weeks' break has changed anything.
Mr Brown enjoyed pre-summer bounce in polls
Mr Cameron has talked of engaging in a "bare-knuckle" fight with Mr Brown - just what his party wants to hear. But now he has to follow through.
Mr Brown, on the other hand, needs to keep his political momentum going and prepare for the inevitable end of his honeymoon period.
Mr Cameron's campaign has not been helped by the recent rows over the party's focus on alleged hospital closures, which saw some of the claims refuted by NHS trusts themselves.
But in the wake of the shooting of 11-year-old Rhys Jones and other recent gun and knife-related crimes, his talk of "anarchy in the UK" may be striking a chord with voters fearful of what is happening on their streets.
He is putting his notion of the "broken society" - an idea fundamentally challenged by the prime minister - at the top of his post-summer agenda, placing a new emphasis on changing behaviour, with a focus on homes and schools
By taking a tough line on law and order - once natural Tory territory - Mr Cameron may believe he can map out some distinctive policies while showing sections of his party who are sceptical about his leadership that he is about more than simply "hugging hoodies".
11-year-old Rhys Jones is the latest victim of Britain's gun culture
He may also seek to exploit the perceived rebellion amongst some Labour MPs - and, according to some reports, ministers - over demands for a referendum on the new EU treaty.
The danger for Mr Cameron is that the prime minister may counter it with suggestions the Tories are back to their "old agenda" and are moving to the right - precisely what Mr Brown's strategy is attempting to achieve.
The prime minister, meanwhile, knows his honeymoon period will not last forever and talk of an autumn election is being played down in Westminster amid fears his current poll ratings may be fragile.
Iraq has once again raised its head as an issue, although the tone of the language from the government is significantly different from Tony Blair's, with the emphasis clearly on future plans to reduce troop numbers further.
And, in any case, many believe the issue does not pose anything like the same level of threat to Mr Brown as it did to his predecessor.
And it remains to be seen just how dangerous the claimed rebellion over the EU treaty really is.
Mr Brown's biggest challenge once the initial post-Blair period has ended is to continue holding onto the agenda and persuading voters they need not look elsewhere for radical new policies.