Stephan Shakespeare is a founder and global CEO of YouGov.

Talk of a Conservative ‘surge’ is probably exaggerated: yes, the budget was well-received by the public as well as by commentators, and it has made the Government look as though it has found a new sense of purpose. But remember how Ed Miliband had a decent bounce when he announced a freeze on utility prices, and it soon faded. Parties generally have a bounce after their conferences even when they had little to say, simply because of the extra attention they receive. And during the last election campaign the LibDems got a huge lift from Nick Clegg’s performance at the first TV debate, yet their hopes of a transformational moment at the polls quickly faded to nothing.

Even a bounce on the back of a good and serious reform (and the improvement in poll ratings has, significantly, been supported by other underlying numbers – for example, Government approval is now at its highest since 2010)) is unlikely in itself to reverse the two powerful trends that lead to coalition: the long-term trend against mainstream parties, and the fact that governments tend to lose rather gain support, even when they are doing quite well.

My view for nearly three years has been that David Cameron is most likely to stay in Number 10 as leader of a slightly weaker coalition, and this rise in the polls hasn’t made me change my mind. Even though the pension reform will make a real positive difference to a significant group of voters, and even if a view is crystallising that the economic recovery is real and will last, outright victory for the Conservatives remains very difficult.

But three things could still happen to change the outlook: Labour could become destabilised by Ed Miliband’s uncertainty, the Tories could become encouraged to take further bold policy steps, and the economy could accelerate and broaden its recovery.

Let’s just consider the second of those – an emboldened Cameron. When he first went for leadership of the party, he presented himself as fresh and driven. He took reputational risks which made him look different to other Conservatives. He presented himself convincingly as in touch and ambitious for change. People warmed to him. But the usual effects of difficult years in government have had their effect: today he tends to look weary and a bit annoyed, and he doesn’t convince us he still has a mission.

Voters expect governments to do things. To solve problems. To create better structures. The Budget announcements were so effective because they had a palpable purpose: politicians were doing the very thing they are there for, grappling with a big, important issue and coming up with a smart, believable answer. They showed that such things are possible – it’s not just a matter of a few tweaks to the messaging. The question going through their minds is probably: should we do more, or is this enough? They could still surprise us all with a late surge of ideas and reforming energy.