Britain's political problem may not be a lack of new ideas, but the growing gap between promises of change and the difficult reforms needed to deliver it.

Prime Minister Andy Burnham's first weeks in office have brought a change in political style, but questions are now emerging over whether the government will deliver substantial changes to the country's biggest problems. Parliament's return is expected to bring sharper scrutiny of spending, public services, defence and the economy.

The challenge is particularly difficult because Britain faces high borrowing costs, pressure on public finances and persistent economic uncertainty. The government's October Budget will therefore be an important test of whether its political ambitions can be matched by available resources.

There is also a wider lesson for Westminster. Changing the person at the top of government does not automatically change the country's underlying problems.

Voters increasingly expect governments to improve public services while keeping taxes, debt and living costs under control. That combination is difficult—and avoiding the hardest choices may only postpone the problem.

The real test of the Burnham government will therefore not be whether it looks different, but whether Britain actually feels different after the first year.