With the odds shortening on a 2019 General Election, businesses are paying closer attention to policy announcements from the Opposition. So it was standing room only at the UK Finance HQ in London last week as John McDonnell unveiled the Labour Party's new approach to tackling climate change and supporting sustainable investment.
Labour's plans are radical, with a proposal for a more interventionist state, as well as some headline-grabbing sticks to beat private sector businesses that aren't doing enough to address climate change. While there were hints of carrot, you had to look hard to find them.
The shadow chancellor began by committing a future Labour Government to securing net zero carbon emissions by at least 2050 (or earlier if possible), and harnessing 'the full might' of the Treasury to invest in green infrastructure.
The plan is for a £250bn investment programme over 10 years, funded by government bonds. The priorities would be alternative energy sources, a carbon neutral transport system, the conversion of the industrial sector to low carbon production, radical reform of agriculture and land use, and energy conservation in residential and commercial property.
The programme would be overseen by a new Sustainable Investment Board, bringing together the role of Chancellor, Business Secretary and the Bank of England Governor.
Where the shadow chancellor began to lose the room was when he announced a new independent review into how the 'shadow banking' sector causes or exacerbates the problem of climate change - and where and how it could be providing solutions. Commercial banks, investment banks, pension funds, hedge funds, private equity, asset managers, derivates and securities traders and exchanges will all be under the microscope.
The review will examine how proposals for an enhanced Bank of England toolkit could be adapted specifically to tackle the financial stability threat of climate breakdown.
Ultimately Labour wants to 'ensure adequate policing of investments using the mechanisms available to require companies to live up to their climate change responsibilities'.
One key threat being floated is legislation to delist any London-listed company that fails to contribute to tackling the climate change crisis.
While there were some hints that incentives would be required to divert investment away from fossil fuels and into environmentally sustainable activities, the detail was scant.
The response from business representatives was swift and scathing: 'financial totalitarianism' screamed one, 'infantile mumbo-jumbo' sneered another. Others were more measured, expressing concern about the risk to London's place as a global financial centre.
In the ensuing Q&A, the shadow chancellor did open the door to further consultation on the party's proposals. 'Here's our policy. If you don't like it, if you agree with the objectives, find me another route. If you can't do that, come in and advise us on the route that we're taking, and how that can be done more constructively.'
In the event of a snap General Election, you can expect business to do just that.