Brexit: London Boroughs and MPs

In a post here in January about the 2016 Richmond Park parliamentary by-election, I pointed out that “Anyone who attempts to look at [the relationship between the by-election and the 2016 EU Referendum] will encounter a problem: the Referendum results in London were reported at borough level, not by parliamentary constituency” and that I would “provide some further analysis of the London boroughs and the parliamentary constituencies within their boundaries” so here it is, for what it’s worth.

What constitutes London? Its orbital motorway, the M25, might provide a clear physical boundary but many people outside it earn their living in the city and its area assessed in terms of economic impact spreads a long way. For political purposes London is the combination of its 32 Boroughs with, at their centre, the City of London, both of these having Mayors. Within that London, there are 73 Parliamentary Constituencies (PCs). However, the City of London does not have its own MP, sharing one with next-door Westminster. So, for the purposes of most of what follows, I have combined the separate Referendum results for the Borough of Westminster and the City into “Westminster and City of London”.

A further complication is that 10 of the PCs straddle two LBs, Richmond Park being an example with its voters in Richmond upon Thames and in Kingston upon Thames. The table below shows how seats are distributed across the boroughs, 18 out of 32 sharing a PC with another. After the 2015 election the majority of London seats were Labour, and there was only one Liberal Democrat.

The 18 LBs and 10 PCs are shown below:

The 2016 EU Referendum introduced a new dimension into UK politics. The most pro-Remain area in the UK was Lambeth LB at 78.6%, 30.5% more than the UK average. But another London borough, Havering, at 30.3% was 17.8% below. 369th of the 380 UK reporting areas, Havering was almost as inclined to Leave as Boston in the East Midlands, the 380th at 24.4% Remain. The Remain and Turnout percentages for the LBs are shown in the chart below:

The chart shows that in London with exceptions (eg Richmond upon Thames) the relationship between Remain and Turnout was slightly inverse: that is to say, as the first went down, the second went up.

Across the UK, turnout for the Referendum in 2016 at 72.2% was higher than in the previous year’s general election at 66.4%. This was the case in most of the London PCs, but not all:

The LBs where turnout was less in 2016 than that of constituent constituencies in 2015 are shown below:

The Lewisham turnout reduction is unusual, involving all three of the PCs in the borough.

Finally, the chart below brings together the 2016 Remain results for the LBs (measured relative to the UK outcome – x-axis) and the majority in each of the PCs in 2015 (y-axis), both being percentages. PCs spread across two LBs are denoted with hollow bullets and linked with dotted lines. The outcomes of the two London by-elections in 2016 (Tooting just before the Referendum and Richmond Park nearly five months later) are indicated by the vertical arrows leading to stars.

The bullets with green shrouds indicate the PCs of MPs who voted against exercising Article 50 on 8 February. Not surprisingly, these represented constituents from LBs that had favoured Remain. The Lib Dem MP for Carshalton and Wallington is a notable exception. The MPs for the two PCs with voters in boroughs with marked differences in attitude to Remain (Erith and Thamesmead in both Bexley and Greenwich and Ruislip Northwood and Pinner in both Harrow and Hillingdon) did not vote against Article 50.