Two housing tax announcements were made in the Budget last week. Only one of the two had a large-scale reaction in the media and from wider commentary. Both are important but for different reasons.

The Mansion tax surcharge on very expensive homes is a tax that has been on the agenda for a long time, till at least the Lib Dem manifesto in 2010, but now has finally seen the light of day. It is a Council Tax surcharge (for England only) and will require revaluing of the highest value properties. Those valued at above £2 million will pay a progressive annual surcharge of between £2,500 and £7,500, with revenues returning to HM Treasury. It is estimated that it will raise £400 million in 2029-30. With a valuation exercise to come in 2026 to identify such properties, it will be 2028 before it comes into force. Although this is for England only, one imagines that it will play into the current proposals to revalue Council Tax in Scotland and Wales.

The second tax reform is to increase rental income tax paid by private landlords. There was earlier discussion of adding national insurance contributions to landlord’s income from renting, but instead the relatively simpler innovation of setting a specific tax surcharge on all private landlords’ rental income of 2% at the relevant marginal income tax rate has been chosen. The changes will come into effect for fiscal year 2027-28 and the Governments in Scotland and Wales will engage with the UK government about how these rates may be operated or modified within their respective fiscal framework-based tax powers.

Much has been made about the excessive briefing and floating of ideas in the run-up to the Budget. For those interested in housing taxation, this went back to late summer when, usually, the Guardian newspaper discussed a range of tax possibilities concerned with taxing housing wealth. This included capital gains tax, council tax reform, the ‘mansion tax’ and Tim Leunig’s proposal to combine the revenue from both Council Tax and Stamp Duty Land Tax. They also discussed different ways to raise tax revenue from private landlords, including adding National Insurance Contributions to taxable rental income (which I felt stretched arbitrariness in how we frame and apply the tax system).

The two proposals advanced in the Budget combine the desire to challenge arguably unreasonably light or absent tax on housing wealth held by owners or private landlords, which would of course seek to also increase exchequer revenue, but also start to address the inequalities of how we tax asset inequality in a society increasingly stratified by wealth rather than by income.

It is in this context that it has been striking to see the Mail and Telegraph predictably condemn the tax on high value homes, presumably elements of their readership own such homes or realistically (or not) aspire to do so. But other than interest groups, little critical commentary has followed the income tax increase on private landlords – a tax increase that follows on from previous reductions landlord mortgage interest tax relief, their continuing higher capital gains tax liability and significant surcharges on stamp duty land tax when purchasing homes to rent.

My own reflections are as follows. The Mansion Tax or Council Tax surcharge is a missed opportunity to reform Council Tax and tax housing wealth more systematically. It makes no sense to revalue the top end of the housing market only but not to revalue all properties in England. With solid plans to revalue the Council Tax in Scotland and Wales, England may shortly be the only nation of the three sticking with 1991 property values as the reference point for a property tax. I would therefore like to start the campaign to argue for a comprehensive and not just a top end revaluation of the Council Tax in England – it is truly a terrible value for money proposition not to do so.

Second, I don’t support the landlord income tax surcharge. Our tax system is now clearly biased against private landlords on multiple fronts, and I am not convinced that this does much good for the housing system at all. The benchmark tax system for businesses is now a long way removed from the treatment of private landlords.

Many do wish to see a rapid withdrawal of particularly small-scale private landlords from housing in our cities and nations across the UK. But be careful what you wish for. If the argument is that landlords are making excess profit or extracting economic rents and therefore should be punished, they will exit the sector, but the properties will go to other larger landlords, or to first time buyers not constrained by mortgage regulatory constraints; only a few properties will find their way into social or affordable housing.

Actively pursuing policies in this way to reduce a PRS that does house many income precarious households needs to be balanced by a rapid expansion of social and affordable housing supply. Otherwise, reducing the supply of the PRS in the short to medium term is just going to increase scarcity and put upward pressure on private rents. Economists criticise rent controls for consequences such as reducing supply in controlled markets, but the outcome will be in the same ballpark when governments attack landlords in this way through the tax system. In a time of housing emergency, it does not contribute to a better functioning housing system.

• This article was originally published on the UK Collaborative Centre for Housing Evidence (CaCHE) website.