After the discovery, mid-campaign, that their candidate was an anti-Semite, the Labour Party is under fresh pressure over its recent win in the Peterborough by-election – over allegations of electoral fraud.

Despite earlier denials, Sunday Times investigation has revealed that Tariq Mahmood, a convicted vote rigger, played a leading role in the party’s operation in the seat, which it won by fewer than 700 votes.

Activists on social media described him as the ‘mastermind’ of the campaign – despite is being expelled from Labour in 2008 after a court heard he was once at the centre of a ‘massive’ electoral fraud operation in this very constituency.

Now the police are reportedly investigating five separate allegations of electoral fraud, including one aimed at several men who apparently boasted on social media of burning over a thousand Brexit Party votes.

A police spokesman summarised the allegations as “bribery and corruption x1, postal votes x3 and breach of the privacy of votes x1.”, although the Council has taken pains to stress that, as yet, there is no evidence of wrongdoing.

These problems are not new in Peterborough, nor confined to Labour. Raja Akhtar, a Conservative former mayor of the town, was also jailed for three months in 2008 after being convicted on one count of forgery.

So this problem should have been on the radar before now. And Stewart Jackson, Peterborough’s former Conservative MP, tried to put it there when he organised a Westminster Hall debate on the subject in 2015.

In it, whilst he conceded the importance of tackling in-person impersonation and voter intimidation, Jackson focused on the challenges posed by postal vote fraud, as well as the evidence behind the Electoral Commission’s belief that it appears more prevalent “in areas which are largely or predominately populated by… those with roots in parts of Pakistan or Bangladesh.”

These dangers are real. One of the great virtues of the traditional ballot box, for all it vexes some modernisers, is that the secret ballot is relatively easy to maintain. Systems which allow voters to cast their ballots at home – whether that be postal votes or future innovations such as mobile or online voting – expose vulnerable electors to having their vote monitored and pressured. As Jackson argued:

“The reciprocal, hierarchical and patriarchal nature of kinship networks may mean that pressure is put on people to vote for particular candidates or parties, especially within family groups.”

Yet despite a concerted and not uncontroversial effort to crack down on electoral fraud, for example with a voter ID pilot, thus far the Government has not signalled any decisive action on postal votes, despite their seeming to be by some margin the most serious vector for such crimes.

There may be disadvantages to the Party in doing so (perhaps Conservatives are more likely to benefit from today’s easy availability of postal voting) but failure to take action will make the Government’s current campaign against voter fraud ring hollow – or worse, like the partisan quest for an unfair advantage its opponents claim it is.