The political economy of Scottish independence is a sub-plot of Brexit that has suddenly been thrown back into the spotlight.

One issue that has now taken on entirely new dimensions is Scotland’s financial sector. In the independence referendum, the argument was that big banks could leave Scotland for the City of London in the event of independence. Indeed, RBS and Lloyds sensationally threatened such a move just days before the referendum vote.

This time round, the tables appear to have been turned. Brexit has led to question marks over whether London will remain one of the world’s pre-eminent financial centres. The New York Times has reported that “the race is on to be the new London”, with one anonymous banking executive telling the paper that it is considering moving between 10 to 40 per cent of its workforce out of the City.

Some supporters of Scottish independence have jumped on this new terrain to declare an independent Scotland in the EU open for banking business. SNP MP Pete Wishart has argued that, post-Brexit, “overtures” should be made to “international multinationals”. Business for Scotland chief executive Gordon-Macintyre Kemp was more direct in The National, writing that a “cash bonanza” could be heading north if Scotland becomes independent.

“Financial services is worth about £7 billion to Scotland’s economy,” he said. “Independence within the EU managed correctly could see that double and along with other relocations create an instant, independence-related finance, exporting, manufacturing and construction/property price-led economic boom for Scotland.”

Independence supporters should take a step back here. First, there is a difference between banks threatening to abandon the City of London and it actually happening. The key here is whether banks retain “passporting”: the right to trade in financial services across the EU. You can be sure that George Osborne and his Tory acolytes will give up pretty much everything else in negotiations with the EU to protect the City. For them, nothing is more important.

Secondly, and more importantly, not all opportunities are desirable. Do we really want to turn Edinburgh into a mini-London? The effects of a finance-dominated UK economy are well known: grotesque levels of inequality nearly unparalleled across the EU, in terms of income, wealth and geography. Former Business Secretary Vince Cable was not wrong when he described London as “a giant suction machine draining the life out of the rest of the country”.

Mr Macintyre-Kemp is wrong to conflate growth in manufacturing and exports with finance-led growth: increasingly the two are exclusive of one another. The Bank for International Settlements, known as "the central bank of central banks", found that “manufacturing sectors …suffer disproportionate reductions in productivity growth when finance booms”.

The authors found this reduction to be worth about two per cent and conclude: "By draining resources from the real economy, financial sector growth becomes a drag on real growth."

This analysis is increasingly popular among economists who are trying to identify why the financial crash in 2008 has been followed by eight years of stagnation. Many are concluding that the weight of household and private sector debt, which has grown by £37 trillion worldwide since the crash, is having a "parasitic" effect on the real economy, holding down productive investment so that banks can accrue debt repayments.

Furthermore, having a bigger financial sector can increase the vulnerability nation states have to a future financial crisis. In 2014, credit rating agency Standard & Poor argued that Scotland’s financial sector was “unusually large”, and that a “normalising” of its size could be a good thing for an independent Scotland’s credit rating as it would reduce the “contingent liabilities for the state”.

At the time, Mr Macintyre-Kemp concluded from this that “the perception of Scotland’s credit-worthiness could be even stronger if one or two banks left”. He was more right in 2014 than in 2016.

An independent Scotland’s economic future should not be pitched on becoming a pre-Brexit Britain. To do so would only be to repeat the mistakes made in the Thatcher-Blair-Cameron years. Scotland is well placed to get ahead in the information revolution of software-led technologies such as advanced manufacturing and robotics that look set to be the future for the global economy.

A high-skill, high-value, high-productivity re-industrialisation model is where an independent Scotland’s economy should be heading – not the UK’s failed casino capitalism.

Ben Wray is CommonWeal head of policy and research.