MPs price climate opposition at triple its measured level, Cambridge survey of 100 finds

A University of Cambridge study that surveyed 100 sitting MPs found that members of the three largest parties in the House of Commons systematically overestimate how strongly the public objects to carbon reduction policies ^[1][2]. The size of the error matters more than its direction: on one policy MPs priced opposition at three times the level polling recorded, which recasts a stalled agenda as a measurement failure inside Westminster rather than an absence of public consent ^[4][6].

The two test policies were mundane. Asked about grants or loans for insulation for every household with an energy efficiency rating of C or below, MPs collectively put public opposition at around 18 percent; polling from earlier in the year found 6 percent ^[4]. That is a 12-point overstatement, a factor of three ^[6]. Asked about rejigging tax on products so that it varies according to environmental damage, MPs estimated 38 percent opposition against a measured 20 percent, an 18-point overstatement ^[5][7]. Averaged across the two policies, MPs saw 28 percent opposition where polling found 13 ^[21].

The study was published in Communications Sustainability by researchers at Cambridge's El-Erian Institute of Behavioural Economics and Policy and the Cambridge Political Psychology Lab ^[3]. Lead author Dr Lisa-Maria Tanase says the pattern is not wishful thinking or the projection of politicians' own worldview: on average, even MPs who support a climate policy think the public is more opposed to it than it really is ^[9]. MPs who back climate policy and MPs who oppose it overestimate resistance alike, which Tanase says is likely to limit the range of options they consider politically feasible ^[8].

The second finding concerns the shape of opinion rather than its level. Polling showed a 12-percentage-point difference in support for the insulation and product tax policies between Labour and Conservative voters; MPs estimated more than double that, at around 25 points ^[12]. They put the Liberal Democrat to Conservative gap at 30 points against a measured 14 ^[13], and inflated the 2-point Labour to Liberal Democrat difference to nearly 5 ^[14]. The largest distortion concerned Conservative voters, judged on average 12.6 points less supportive than the general public when polling put the gap at 2.5, an overestimate of about fivefold ^[15]. Tanase notes that previous studies link exaggerated perceptions of polarisation to reduced willingness among politicians to engage in cross-party dialogue ^[18], and that environmentally supportive Conservative voters may end up feeling misrepresented ^[20].

The operative result is the link to behaviour. MPs' perceptions of public support for the green product tax predicted their willingness to advocate for it even after their personal belief in the policy was accounted for, with those who thought voter support was lower less willing to speak up in public ^[16]. The researchers say this may be the first data-led evidence for a spiral of silence in Westminster, where skewed perceptions of public sentiment among politicians reduce political support for a policy ^[17]. Tanase attributes the skew to information environments, arguing that social and traditional media disproportionately reflect vocal segments of society rather than the full distribution of opinion ^[10], producing what she calls a funhouse mirror effect ^[11].

Two limits are worth holding onto. The outcome measured is stated willingness to promote a policy, not votes cast or bills tabled ^[16], and MPs' estimates were compared against polling conducted earlier in the same year rather than in the same week ^[1]. Researchers also asked MPs to estimate how many other parliamentarians would back a green product tax ^[19]; that second-order belief is where a correction, if anyone attempts one, would show up first.