Yeah tax and policy, his commentary is pretty neutral and easy to understand. Income tax is the most progressive tax we have, much more effective to raise it. Instead the greatest impact is now on low earners. Likely there's more to come as well.
Yes, income tax taken via payroll is the only reliable means of raising revenue. Because every other form of taxation taxes an activity for which there are alternatives (I.e. raising taxation can mean the activity you are taxing reduces and you simply end up getting a higher % of less money).
The rise in employer's NI contributions is a case in point. This is introducing an extra cost to employers of employing people in the UK, which, actually, they don't have to do. Coupled with the increase in minimum wage and Rayner's planned changes to employment rights legislation (which will make it very hard to get rid of poorly performing or badly behaving employees), the likely outcome will be more offshore outsourcing contracts such as foreign call centres and service centres, small businesses making do with less staff and so although Labour have calculated "if I raise employer NI it will generate X", that's merely an "on paper" assessment. And as most analysts expect unemployment to rise you'll see a decline in income tax and NI revenue and an increase in benefit payments.
I'm sorry, but every Labour government in history has been economically illiterate. Labour have invariably left office with the UK in an economic crisis and it always starts with excessive budget deficits being run due to the casm that always exists between what Labour think they'll raise to fund their public spending and what actually comes in.
Last Labour government came to power in 1997 and by 2004 the EU opened an excessive deficit procedure against the UK under the stability and growth pact. Despite committing to bring the deficit to within 3% of GDP by 2006 (the UK weren't full members of S&G not being a euro member and complied with excessive deficit procedures on an agreement/voluntary/best endevours basis), the government failed to meet this target and the procedure was extended several times. By 2010 when Labour left office, the deficit was 10% of GDP meaning the UK was forced to borrow 10% of its GDP every year.
It took Osbourne and Cameron until 2016 to comply with our EU commitments leading to the EU to close the procedure in 2018. I've attached screenshot of the European Council's summary from the abrogation decision.