Businesses will have watched the Labour leadership contest with a mixture of bemusement and alarm.
But to what extent will reality match the rhetoric on some of construction’s most important issues?
On Europe, the arrival of Mr Corbyn heralds a Labour Party that is more sceptical of remaining a member of the EU – though an ‘Out’ position from the Labour frontbench is unlikely.
One thing for sure is that the job of the ‘In’ campaign just got a lot more complicated.
Future political landscape
Stepping between the views of a Labour Party focused on an EU centred around protecting worker’s rights and a Conservative Party aiming to further open markets will require some nimble footwork
Elsewhere, on labour relations we will see a reinvigorated left.
The government’s Trade Union Bill provides a focus for Labour opposition, so expect a great deal of left-wing sound and fury – which will ultimately signify nothing in terms of the government’s ability to pass a bill.
It may in the short term, however, increase the likelihood of strikes elsewhere in the economy as unions seek to flex their muscles.
“Mr Corbyn is not alone in desiring a higher level of infrastructure spend”
Londoners will be hoping that outstanding disputes on the night Tube are resolved swiftly and don’t get caught up in this wider battle.
On infrastructure, the mood appears less concerning. Mr Corbyn is not alone in desiring a higher level of infrastructure spending.
Indeed, many economists and businesses have argued that historic low interest rates mean that now is a once-in-a-lifetime opportunity to invest in infrastructure.
Inevitably, there will be disagreements about specific projects, but a broad consensus persists across the political spectrum that infrastructure needs to be a priority.
Key infra questions
High Speed 2 provides an early test of Labour’s commitment.
While Mr Corbyn has previously been anti-HS2, he has softened his stance in recent weeks, saying that, by the next election, it will be under way and will therefore have to continue.
But what of one of the most high-profile infrastructure projects: airport expansion?
“With John McDonnell as shadow chancellor, the frontbench will be more hostile to Heathrow”
Clearly, with John McDonnell as shadow chancellor, the frontbench will be more hostile towards an extra runway at Heathrow.
Mr McDonnell was suspended from the Commons in 2009 after his mace-grabbing stunt in protest of the decision not to hold a vote on the runway proposal.
But while cross-party consensus is today harder to achieve than it was a week ago, a majority of MPs in parliament remain in favour of airport expansion so a deal remains to be done.
Business will need to hold the government’s feet to the fire as we approach decision-day later this year.
Finally, the Labour team clearly recognises the importance of housing – and, frankly, it’s good to see housing riding high on the political agenda, as decades of dithering have left us with a housing crisis in the capital.
However, Labour’s emphasis on social and affordable housing will need to be tempered with the reality of development economics if housebuilding is to rise.
This will be a particular challenge for newly endorsed mayoral candidate Sadiq Khan, who has made housing one of the centrepieces of his campaign for City Hall.
Above all though, expect a period of flux.
Westminster politics is today more unpredictable than it has been for some time.
David Leam is Director of Infrastructure Policy at London First a former special advisor to the Secretary of State for Transport under Labour