Obviously, the mansion tax policy was debated in some detail on the Floor of the House, and the figures are the ones on which the  Liberal Democrats based their calculations. We said that we would support the policy now, in this Parliament, to alleviate some of the pressure on the lowest earners. We would transfer some of the gains of those who have benefited hugely from the rise in property values, and who could, many feel, contribute towards alleviating the situation at the bottom. That is the purpose of the clause, and the Minister has rightly identified that assessments need to be made of how we calculate the value of a mansion tax. We need to take into consideration factors such as administration costs, how easy a tax it is to collect and administer and what the net benefit to the Exchequer would be. The reason why I flagged up the reductions in terms of the overall headline figure for revenue collected from the ATED relates to the many exemptions that have been factored into the drafting of the tax. Once the various exemptions are taken into consideration, the net revenue figure is much smaller.

I will explain the point of our amendment and how we see it working. We want to see an assessment of the revenue. We feel that the Government have laid the foundations for that by introducing this tax on properties of £2 million and upwards. It will be possible to carry out the same assessment, but not limit it to enveloped dwellings, corporate structures and those that the Government are rightly targeting for current avoidance activity. We see no reason why that assessment could not be extended to properties owned by individuals, which is why we tabled the amendment.

Clause 91 sets out the four bands under which the annual tax on enveloped dwellings would operate. The Prime Minister and the Chancellor have roundly rejected the notion of a mansion tax, claiming it would require mass revaluations. The setting up of the banding system, which would already be in place with this legislation, could provide the template for how a mansion tax could work. That is where the support of the Liberal Democrats comes in. An extension of the banding could easily be achieved based on the Treasury consultation document, “Ensuring the fair taxation of residential property transactions”, published in May last year, in which there is a chapter about introducing an annual charge as part of a regime to tackle tax avoidance on high-value residential property. It is limited only to property owned in companies or partnerships. Noting that properties will be revalued every five years, the document says:

“To assist taxpayers in compiling their annual charge tax return HMRC and the VOA will offer a pre-return valuation checking service to property owners.”

In table 2.A, the document sets out the proposed annual charging structure, and lists the property values and the likely bands that the Government would use: £2 million to £5 million; £5 million to £10 million; £10 million to £20 million; and properties worth more than £20 million.

Therefore, the Government already acknowledge that that kind of assessment and banding is entirely feasible, which prompts the question why they have dismissed it out of hand in relation to properties owned by individuals. Assistance has already been factored in for companies and partnerships to provide the information and valuations necessary in order to charge the annual levy. It would be useful if the Minister could set out why there is such a difference between individual properties and those owned by companies and partnerships.

That brings me back to my original comments related to the concerns about how the potential ATED and SDLT might be avoided by alternative means. Levying the annual charge might not resolve the issue as the Government hope, because it might just result in alternative avoidance activity. That would account for the fairly low revenue sums that are factored into the tax information and impact note. The Opposition are talking about a mansion tax on all properties worth more than £2 million. We believe that while the Government are putting the structures in place to provide support with evaluations—the banding and the property value that the tax will be levied on—they should at least take the opportunity to make an assessment of how the measures could be extended more broadly across the property market. That is the purpose of the amendment: to give the Government the opportunity to undertake such an assessment.