As Bloomberg has reported about the USA (I stress):
Municipal bonds have never been at risk of becoming the next big thing for bubble-chasing investors, like crypto currencies or tech IPOs. But 2019 has been marked by an unusually large stampede into the $3.8 trillion state and local government debt market because of a motive that’s nearly as old as civilization itself: avoiding taxes.
Municipal-bond mutual funds and exchange traded funds have pulled in about $46.9 billion over the last 38 straight weeks. That’s the biggest cash haul since 2010.
Several factors are helping to feed the demand, including interest-rate cuts that have pushed up the price of outstanding bonds and sent the market to its biggest gain since 2014. But a major reason is the tax overhaul that capped the federal deduction of state and local taxes, which caused some Americans to use their investments as a way to drive down what they owe.
This is not the time or place to analyse all the differences between the UK and US tax systems on savings, because there are many of them, and the UK is absurdly generous in the range of shelters it provides. In the US municipal bonds have a tax cap, and sometimes an exemption, that can put them in the place of an ISA in the UK if rough equivalence is sought. And that's one reason for the flood of money: the tax differential is enough to compensate for the higher risk in these bonds when overall rates are low.
Why mention this? Simply because I have long argued (if since 2003 counts as long) that local authority bonds are a key part of the funding for the Green New Deal. And as I have also shown recently, more than 80% of UK private assets are tax incentivised in the form of housing, pensions and ISAs. So what is true of the USA is also true here. And in that case changing ISA reliefs so that ISA funds could only be invested in Green New Deal related assets, such as local authority bonds, backed up by a guaranteed interest rate a little above normal and with an effective asset guarantee, equivalent to the deposit guarantee scheme supplied to banks, would mean a flood of money into local authority bonds to fund the Green New Deal.
It's not rocket science.
It is EU rule compliant.
And it could work.
What are we waiting for? Overnight we could solve the housing issue; transform local power generation and provide funding for local transport. We just need the will to do it.