For many decades progression in British politics has tended to run in one direction – towards Westminster. But the re-emergence of mayoral government across England may mean the national stage will cease to be the ‘be all and end all’ for ambitious politicians seeking to make a difference to the country. Yesterday, Andy Burnham announced he intends to run for the mayoralty of Greater Manchester, and there are a number of factors that mean he is unlikely to be the last big hitter in Whitehall to choose to run for local office in 2017.

A fast track to a bigger, national profile

First, there’s the size of the mayoral mandate, and the public platform that this provides. For example, Andy Burnham secured 24,312 votes in his Leigh constituency at the General Election in 2015. By contrast, Sadiq Khan, the newly elected Mayor of London, received over 1.3 million votes following the allocation of second preferences – the biggest mandate ever secured by an individual British politician.

While Burnham and his rivals will struggle to attract quite that level of support, given the smaller size of the Greater Manchester electorate, these figures do highlight the scale of the personal mandate metro mayors can secure at the ballot box.

And this mandate matters. Securing the support of so many voters immediately attracts wider public attention, allows the mayor to demand significant public platforms to galvanise support for major reforms, and provides them with a powerful base from which to lobby central government for change. In just two weeks, Khan has seen his profile escalate in a way he could not possibly have achieved by continuing his career as a shadow minister. Indeed, he is already among the favourites to be the next Labour leader, just as outgoing London Mayor Boris Johnson remains a front runner to be the next Conservative leader.

The opportunity to govern

Second, although the number does shift from time to time, there are usually only around 20-25 seats at the cabinet table within Westminster. The route to securing one of those posts normally involves having shadowed the department in opposition, or progression through a series of more junior ministerial posts.

But the introduction of fixed term parliaments and five years of coalition government have acted as a constraint on regular reshuffles, and the opportunities for promotion they have historically provided MPs, and reduced the chances of snap elections which could see an opposition party return to government. The fallout of the EU referendum aside, given the current slim Conservative majority, and the uneasy relationship between the Labour leadership and much of the parliamentary party, it is unlikely that this trend will change dramatically in the years ahead.

This will mean that MPs with ambitions of high office will need to think differently about their plans for progression. Select Committee chairmanships have provided an avenue to greater notoriety for some, and it is possible to build a reputation as a formidable campaigner on individual issues as a backbencher. But running a big city would far outweigh both of those options – with the new Mayor of Greater Manchester directly responsible for a budget in excess of £7 billion. For Labour MPs in particular, who may currently fear another nine years of opposition, the pull of securing a mayoral mandate in 2017 – and the opportunity to govern – may be too great to resist.

The chance to affect real change in people’s lives

The mayors that will be elected in 2017 will gain control over elements of local transport, housing, skills and, in the case of Greater Manchester, health care. This provides them with real scope to lead their place, drive through important investments that can benefit the local population, and over time help implement significant public service reforms. Whatever the influence held by MPs, junior ministers and even some cabinet positions to shape a national agenda, they don’t have access to the kind of levers that can deliver this sort of change directly to the places that they represent.

And not only are they close to the frontline of delivery for their place, but unlike even senior ministers or shadow ministers, the new metro mayors will not be a link in a more complex chain of command – they will have no boss other than the electorate. Notwithstanding political considerations, this means they will be more able to act decisively, to a large extent freed from party political or bureaucratic constraints.

Given these factors, it is not fantastical to imagine that by the time of the next general election, being mayor of a major English city region will rank only behind the highest offices of state when it comes to the top political jobs in the country. And it may even be the best spring board to achieving those roles in the future.

Andy Burnham’s decision to stand in Greater Manchester reflects a calculation that ambitious politicians representing areas due to introduce mayors next year should all be considering – if you’re unlikely to become Foreign Secretary, Home Secretary, Chancellor or Prime Minister in the next 10 years, might 2017 be the time to swap Whitehall for the town hall?