The by-elections yesterday were one of the biggest tests of the Conservative Government since Rishi Sunak became Prime Minister.

In the run-up to election day, Sunak repeated that mid-term by-elections are notoriously tough for sitting Governments.

Now that votes have been cast – will the results give any indication of what will happen in the next General Election?

Uxbridge and South Ruislip

Given the big swings to Labour and the Liberal Democrats in the two seats, I am sure that people will be writing about the Conservatives successfully retaining Uxbridge and South Ruislip for some time. The by-election was called after the resignation of Boris Johnson, with all the opinion polls suggesting Labour would win the seat.

Labour’s campaign focused on mortgage costs, local policing and the need for a new hospital. The Conservative campaign focused on the implementation of the Ultra Low Emission Zone (ULEZ) by the Mayor of London, Sadiq Khan – stating that it was a referendum on the policy.

I am sure there will be some brow-beating on whether ULEZ was the deciding factor which helped Steve Tuckwell retain the seat. There was a lower swing of 6.7% to Labour’s Danny Beales, a well-known figure in London’s Labour Party.

In an area where some families owned multiple cars, it was clear that the issue came up on many doorsteps during the campaign. Beales spoke about his concerns about how the policy was being introduced and with the GLA elections taking place next May, ULEZ will undoubtedly remain a big issue in London.

Somerton and Frome

The Liberal Democrats have a notoriously strong, disciplined and targeted approach to by-elections where activists across the country flock to campaign together.

Local Councillor Sarah Dyke won Somerton and Frome with an astonishing swing of 29% to the party. Dyke was a local Councillor at Somerset Unitary Council and held the sustainability and climate change brief.

Overturning a 19,232 Conservative majority is a massive achievement and was in no doubt helped by supporters of other political parties backing her.

Selby and Ainsty

In North Yorkshire, the Selby and Ainsty by-election was called following the resignation of Nigel Adams as part of the fallout from the pending Commons Privileges Committee into Boris Johnson. Selby and Ainsty is a semi-rural seat which had backed the Conservatives since it was formed in 2010.

The swing of 23.7% to Labour went even further to suggest that the Labour Party is on track to form a Government next year. Keir Mather, Labour’s winning candidate, is 25 years old and will be the youngest serving MP in Parliament.

How the by-elections could impact the built environment

Debates about the 15-minute cities and active travel are happening across the country with many local councils adopting schemes to try to reduce the reliance on cars.

But in each case, they face vocal opposition. I can’t see this policy changing, but during a period where there is a cost-of-living crisis, it’s clear that additional costs incurred through policies like ULEZ will be challenged.

It is perhaps ironic that it was a policy introduced by Boris Johnson whilst in the role of Mayor of London!

The famous saying that a week is a long time in politics is often used – but in this case is very apt.

The three main political parties will try to take some comfort from the results. But the double-digit swings in two of the seats will cause stress for the Government – especially with a further by-election expected in Mid-Bedfordshire and potential recall petitions that could lead to elections Tamworth and Rutherglen & Hamilton West.