By-elections have a habit of leaving a mark on UK politics

For the political obsessive, the apparently unconnected areas of Orpington, Glasgow Govan, Glasgow Hillhead, Bermondsey, Eastbourne, Wirral South, Copeland and Clacton have a resonance which gives them a special place in history.

It is one of the many vagaries of the UK’s political system that an individual MP’s death or resignation can set a train of events in motion which make or break a government or a party leader – or in some cases provide the catalyst for new political forces to emerge.

The Orpington by-election in 1962 was one of the latter, with a stunning Liberal victory on a 22-point swing providing a shot in the arm for a party which was languishing at little more than 2 per cent in the polls with just six MPs.

It set the template for a decades-long campaign of attrition by Liberals (and later Liberal Democrats), unleashing activists at carefully-targeted seats to gain high-profile scalps in Croydon (1981), Bermondsey (1983), Eastbourne (1990), Newbury and Christchurch (1993), Romsey (2000) and Richmond Park (2016).

Bermondsey saw Simon Hughes enter parliament on the back of one of the bitterest campaigns in electoral history, as gay rights activist Peter Tatchell became the focus of “loony left” accusations directed at then Labour leader Michael Foot.

The 1990 by-election in Eastbourne played a key role in the demise of Margaret Thatcher’s premiership. Assumptions that Tories would easily hold a safe seat in a vote caused by the IRA’s murder of MP Ian Gow were overturned by a Lib Dem triumph driven by anger over the poll tax, paving the way for the PM’s ousting just weeks later.

As with so many famous by-election victories built on the back of a single issue – Sarah Olney’s capture of heavily anti-Brexit Richmond Park from Zac Goldsmith is another example – Lib Dem victor David Bellotti was himself dumped by the voters of Eastbourne at the next opportunity.

Two Glasgow by-elections provided the springboard for the emergence of new political forces.

Govan in 1973 saw Margo MacDonald increase the Scottish National Party’s vote share by a remarkable 31 points to seize a solid Labour seat in a battle which arguably marked the start of the party’s long march towards dominance of politics north of the border.

Hillhead in 1982 delivered a berth in parliament for SDP leader Roy Jenkins, ushering in a remarkable but short-lived period when the centrist party – later in alliance with Liberals – looked set to break the mould of British politics and replace Labour as the main rivals to the Tories.

Wirral South’s place in political history was sealed by the 1997 by-election which finally deprived John Major of his majority in the Commons, gradually worn down from 21 at the 1992 election by a rapid succession of MPs’ deaths, paving the way to the landslide which brought Tony Blair to power just weeks later.

Clacton in 2014 may ultimately have been the by-election with the greatest significance in political history. Won for Ukip by Douglas Carswell after he resigned from the Commons after defecting from the Tories, it cemented in David Cameron’s mind the need to offer a referendum on EU membership in his manifesto for the next year’s election – and we all know how that ended.

The significance of Copeland, when a long-standing Labour seat in Cumbria fell to the Tories, was not immediately apparent at the time. But with the benefit of hindsight, Trudy Harrison’s 2017 victory was an early glimmering of the Red Wall phenomenon which saw Leave-voting working-class seats in the north and Midlands tumble to Boris Johnson two years later.

Yours,

Andrew Woodcock

Political editor