Lewis Baston is author of Reggie: The Life of Reginald Maudling and several books about British general elections. He is a consultant on politics, elections and constituencies.

This month marks sixty years since the first post-war example of a sporadic but persistent feature of British political life – the Liberal by-election triumph.

On 27 March 1958 the Liberal candidate Mark Bonham Carter gained the Torrington constituency from the Conservatives, the first Liberal by-election gain since 1929.

Our collective memory tends to recall the 1950s as a tranquil period in British political life, but this is not entirely accurate. Macmillan’s government started shakily in 1957 with the hangover from the humiliation at Suez and some Cabinet splits; Labour gained Lewisham North, the first time since 1939 that the opposition had gained a seat won by the government at the previous general election.

The bumpiest period, though, was the first half of 1958. The entire Treasury ministerial team resigned in January because the Cabinet would not agree sufficient expenditure control, an event brushed off by Macmillan as a ‘little local difficulty’. More by-election disasters followed for the Government.

The movement of opinion in the February 1958 by-election in Rochdale would still be regarded as freakish and shocking if it were to happen in today’s more volatile political environment. It had a stunning impact in 1958. For the Conservatives not just to lose the seat, but to sink from first to a poor third place with a loss of 31 per cent in share of the vote, was a huge movement in the more stable world of the 1950s.

Although Labour gained the seat, the dashing Liberal candidate Ludovic Kennedy made a lot of the weather. Rochdale had even more of an impact because it was the first by-election campaign to be covered on television.

The next two seats to be defended by Macmillan’s Conservatives were Glasgow Kelvingrove, lost to Labour on 13 March, and then Torrington in west Devon. Torrington was a rural constituency, its main towns being Bideford, Okehampton, and Great Torrington, and on the face of it a very safe Tory seat.

But as happens when the two main parties seem to have a near total grip (the combined Conservative and Labour share in 1955 had been 96 per cent), there are undercurrents of support for political positions that are not represented by the leadership of the two parties and voters who feel at best conditionally loyal to the big party of their choice.

Torrington, like many seats in Devon and Cornwall, had a submerged Liberal tradition. The by-election was caused by the death not of the incumbent MP, George Lambert, but that of his father – whose name was also George Lambert. Except for a break in 1924-29 there had been Lamberts representing Torrington and its predecessor constituency South Molton since 1891. The original Lambert stood down in 1945 and received a hereditary peerage, and on his death in 1958 his eldest son became a viscount and could no longer sit in the Commons.

Lambert was elected as a Liberal until 1931 but went with the National Liberals when the party fragmented, and from 1950 onward his son held Torrington as a ‘National Liberal and Conservative’. For all its safe centre-right status, the constituency had never elected a straightforwardly Conservative-branded MP since it was created in 1885. In the election of 1918 it was one of a small number of constituencies to have stuck with Asquith’s Independent Liberals.

Mark Bonham Carter, the Liberal candidate in the 1958 by-election, was no ordinary Liberal of the suburbs or the shires. He was a sort of Liberal aristocrat, the grandson of Asquith, a Liberal Prime Minister, and brother-in-law of the contemporary leader of the Liberal Party, Jo Grimond. Bonham Carter evoked confidence and competence, and a memory of when the Liberal Party was a powerful force in the land.

His local credentials were tenuous – he had contested Barnstaple in 1945 – but locality was less important back then and Conservative candidate Anthony Royle, an insurance broker and Young Conservative activist, was not very local either.

Following Rochdale, by-elections had become exciting for the politicians and the media, and even the voters. The by-election campaign gripped the interest of the Torrington electorate. A public meeting in Okehampton a couple of weeks before election day attracted over 200 people and was standing room only. This was all the more remarkable given that the speaker, Anthony Wedgwood Benn, was a relatively little known rising star in a party which stood no chance of winning the by-election. It was an improvement on the other meeting Benn held in Torrington, where he noted in his diary:

‘The first meeting drew in six people. The chairman said it was because of a Methodist film show in the village hall. It was a more original excuse than the weather, which is always too bad for people to come out or so good that they’re gardening.’

The turnout for the Torrington by-election was high – 80.6 per cent. Another sign of Torrington’s Liberal element was the sharp fall in participation after the independent Liberals stopped contesting the seat – turnout had been a very below-average 69 per cent in the 1955 general election. After a recount, the result was declared to widespread surprise – Bonham Carter had won by 219 votes.

The Liberal hold on Torrington was brief, as Bonham Carter lost the seat back to the Conservatives in 1959. It took until 1995 for Torrington to return to the Liberals, and that was through the defection of Emma Nicholson, the incumbent Tory MP, to the Liberal Democrats. By then, the seat was known as Torridge and West Devon and covered a somewhat bigger area. The seat remained with the new Lib Dem candidate John Burnett in 1997, who held the seat until he stepped down in 2005, when it flipped back to the Tories.

Geoffrey Cox has held the seat since then, for the first two elections with narrow majorities and then more comfortably – first over UKIP and then over Labour. The last two elections are the first in the history of the seat in which a Liberal candidate has not either won or come second.

After ceasing to be an MP, Mark Bonham Carter remained a close adviser to Jo Grimond and fought Torrington again in 1964. He subsequently went into broadcasting. His daughter Jane Bonham Carter has also had an illustrious career in broadcasting and politics. She received a life peerage in 2004, the only time a family has had life peerages in three successive generations – some hereditary peerages have a weaker track record than this.

Anthony Royle, the defeated Conservative candidate in Torrington, did not see his political career blighted – in contrast to Peter Goldman who lost Orpington in 1962. He was elected at the 1959 general election in Richmond, Surrey, and held the constituency until he retired in 1983. The forces of Liberalism pursued him there and his majority dwindled from over 14,000 at his first election to the 74-vote margin his successor Jeremy Hanley enjoyed in 1983.

Although Torrington was recaptured, the 1959 election was not a complete victory for the Conservatives in their effort to nip the Liberal revival in the bud. The neighbouring seat of North Devon, which had similar political traditions, went to Jeremy Thorpe, who became leader of the party in 1967 and had some subsequent adventures. The Liberal tradition reawakened in other seats in the South West, contributing one strand of the party’s electoral appeal – the other followed a few years later with the more famous by-election win in Orpington in 1962.

The Liberal by-election threat never went away after Torrington. Harold Nicolson recognised in his diary the day after Torrington that: ‘This is a most important political event, since all those who dislike both Tory and Labour will in future feel that it is not wasting a vote to vote Liberal’.

The conditions for Liberal by-election wins emerged again and again over the years – Orpington, Isle of Ely, Eastbourne, Newbury, Richmond Park… and the formula proved adaptable for seats without much of a Liberal tradition such as Sutton & Cheam, Crosby, and Romsey.

By-elections can matter. The biggest consequence of a Lib Dem victory was probably what followed Eastbourne in 1990, the election when the ‘dead parrot’ squawked once more, scared Conservative MPs and led to the fall of Thatcher. Ribble Valley, in March 1991, went on to kill the poll tax, or at least bring its execution date forward.

There really is very little that the Conservatives can do to stave off their opponents if the stars are aligned for a by-election shock. The best advice is not to have by-elections in the first place, and this has been implemented in recent years as best the Conservatives can manage. Resignations for career or family reasons have slowed to a trickle: there has been one Conservative vacancy this century arising from that source, namely Corby in 2012.

The Conservative whips also seem to have instructed their charges not to die, or – given the cussedness of some MPs who would deliberately not do as they were told – have been surreptitiously feeding them the elixir of eternal youth. The last Tory MP to die in office was Eric Forth (Bromley & Chislehurst) in May 2006. Since then, there have been 15 Labour MPs who have died in office, plus one (Marsha Singh of Bradford) who died very shortly after resigning on grounds of ill health. I’m no actuary, but it does seem strange that two older, more male, more stressed and more sedentary sub-sections of the population should have such divergent outcomes.

The most effective way yet found to prevent the Liberals from threatening Conservative seats if a by-election does happen was the coalition agreement of 2010, which instantly removed the Lib Dems’ plausibility as a vehicle for mid-term discontent.

However, nature abhors a vacuum and another protest party, even more oppositional and opportunist than the Lib Dems, sprang up and inflicted its own by-election defeats on the Tories in Clacton and Rochester in 2014. Arguably, UKIP’s electoral threat was more consequential in two years than the Lib Dems in 55 years, in that it led to David Cameron’s promise in 2013 of a European referendum and all that followed.

Now the dust has settled the Liberal vote in Torridge & West Devon, and places like it, seems scattered among other parties and nearly dormant. But it does not look as dormant as it did in 1955. If the whips are wise, they will continue to administer that elixir of life to their MPs.