Updated: “Grey Belt” increases support for house building

Back in October 2023, we wrote about which kinds of arguments might increase support for developing the Green Belt. In the same week, the Labour leadership coined a phrase that gave us a ready headline for that earlier post. In promising to rethink Green Belt allocation, Sir Keir Starmer said:

“But where there are clearly ridiculous uses of [the Green Belt], disused car parks, dreary wasteland. Not a Green Belt. A Grey Belt. Sometimes within a city’s boundary. Then this cannot be justified as a reason to hold our future back.”

Stack works at the intersection of policy, communications and public opinion. We have done lots of work to understand attitudes to development, and thought “the Grey Belt” an inspired label, echoing the main finding in that original post: people are persuadable about development, but - as is the case with many policy issues - they think and talk about it in different language to policymakers.

To test whether “the Grey Belt” is indeed an effective piece of communication, we incorporated it in London-wide polling we conducted in January 2024 to understand attitudes in the capital to different types of development on different types of land.

People respond positively to the idea of developing the “Grey Belt”…

The results are striking. We asked:

“In principle, to what extent would you support or oppose the following in your local area…”

The chart below (Figure A) plots net support (that is, the total saying “Strongly” or “Tend to” support, minus those saying “Strongly” or “Tend to” oppose) for developing on each of the listed types of land (with our own descriptors). The “National” comparator comes from the Stack Omnibus: we posed the identical question to a 1,500 representative sample of the country as a whole, during the same period as the London poll was in field.

Fig A. Net support for developing different land types

…including those who oppose house building in their local area

Developing brownfield land is the lever governments often try to pull, in the belief that development of the Green Belt is untenable politically. As our earlier research showed, that assumption is itself flawed. It is notable not only that “the Grey Belt” options receives such positive net support in comparison with a purer “Green Belt” answer, but that it does so even when that option itself includes explicit mention of the Green Belt (“…for example wasteland, former land-fill sites in the Green Belt”).

But what is particularly encouraging for those who want to see more development is that the Grey Belt concept resonates even with those opposed to housebuilding in their local area:

Fig B. Support for building on Green Belt and Grey Belt among those opposed to development (i.e. answering “Strongly oppose” or “Tend to oppose” to “more homes being built in [my] local area”). Source: Stack polling of London adults

Earlier in the survey we asked:

“To what extent would you support or oppose more homes being built in your local area?”

Figure B groups together all opponents of development in the local area, and even among that group we see a substantial increase in support (and an equally important decrease in opposition) for development on the “Grey Belt” compared with the same group’s support for development of the Green Belt.

Below is the relevant portion of our earlier blog from October 2023, which can be read in full here

What changes opinion on greenfield and green belt building?

Arguments:

Affordability/Affordable housing argument

“It costs a lot more to build on brownfield sites (land that has been built on before), which means many fewer affordable homes, social housing and council housing can be built on brownfield than on greenfield or Green Belt land. In other words, building on greenfield or Green Belt land will deliver many more new affordable homes, social housing and council housing than building on brownfield land.”

Biodiversity and green space access argument

“The majority of land in the Green Belt is agricultural land with no public access and limited biodiversity value. (The Green Belt is land set aside to limit the spread of cities.) Developing some parts of the Green Belt could make more green space accessible to people, and enhance biodiversity.”

Economic growth argument

“47% of the UK’s wealth is generated by just 10 of our cities. Academic studies have shown that the Green Belt around these cities limits their ability to grow, and therefore limits their potential to produce more money for investment in public services or cutting taxes.”

To explore which arguments can move public sentiment on house building on greenfield and green belt land, Stack carried out a 2,500-person poll of English adults. In this poll we presented several arguments for building more homes on the greenfield and green belt land and analysed how these arguments swayed respondents. First, respondents were asked about their support for greenfield or Green Belt building with no further context, using similar wording to that used in previous polling by Ipsos.

Then, to explore what moves opinion on this subject, we asked about support for greenfield/Green Belt building alongside several commonly used pro-development arguments stating that greenfield or Greenbelt building can: provide more affordable housing; improve access to green space and biodiversity; and drive economic growth (Exact question phrasing shown on the right).

Figure 2 shows that when asked initially, before being shown any pro-building argument, the English public opposed building on greenfield and Green Belt land (Net Support -6%). We find that each argument for greenfield and Green Belt building increases support for building in respondents’ local areas.

Vitally, these arguments can also persuade NIMBYs: opposition to greenfield or Green Belt fell under each argument we presented. Analysing these questions sequentially we can see that support for building grows following an “affordable housing” argument (Net Support +9%) and peaks following a “biodiversity and green space access” argument (Net Support +11%).

*Fig. 2. Flow charts of support for local house building per argument*

Not all arguments for building on greenfield and Green Belt land grow support effectively. After hearing an “economic growth” argument we find that support among the public for Green Belt building falls (Net Support +7%). However, it is important to note that the “economic growth” argument did not increase opposition to Green Belt building, rather the reduction in support is mostly driven by respondents shifting from a supportive position to a neutral position.

Who are the NIMBY’s and who supports building?

To examine who the NIMBYs in our sample were we modelled the results of our poll. From the results of this model, in Figure 3, we can see which demographic groups were more likely to be NIMBYs compared to others.

Older people and especially older homeowners are among the most likely to indicate that they oppose building on greenfield and Green Belt land. Although older mortgage holders are slightly less likely to report NIMBY tendencies compared to older people who own their home outright. Comparing across political parties we find that Conservative voters are significantly more likely to be NIMBYs than Labour and Liberal Democrat voters. Regionally, the East of England and the South East are shown to be strongholds of English NIMBYism with respondents in the East Midlands and the North West also showing a slight tendency for NIMBYism.

On the other hand, in Figure 4, we can see groups who were more likely to support house building on greenfield and Green Belt land in their area (YIMBYs). Younger renters, Londoners and Liberal Democrat voters are all shown to be more likely to support house building. Breaking other trends, mortgage holders aged 65+ are more likely to be YIMBYS than mortgage holders aged 35 to 64. These respondents who continue to hold a mortgage later in life, and therefore may have spent longer struggling to get on the housing ladder, are more open to expanding the availability of housing in their area.

What persuades the NIMBYs?

Our research suggests that more than a third of NIMBYs are persuadable. Figure 4 shows that after being presented with arguments in favour of building on greenfield land or the Green Belt as many as 43% of those who originally opposed building moved to a more positive or neutral position. Breaking this down we find that a biodiversity argument is the most effective in neutralising NIMBYism, ameliorating 43% of opposition to home building on greenfield land or the Green Belt. An affordability argument is found to be the least effective, persuading only 38% of NIMBYs overall; this argument was especially weak among NIMBYs aged 65+, reducing opposition by only 30% in this group.

Our research suggests that there is a route forward. Persuading NIMBYs to support house building on greenfield and Green Belt land with arguments centred around biodiversity and green space access shows the most promise. Effective communication and well-crafted arguments can play a crucial role in ensuring that a programme of reform receives public backing.