Barack Obama’s victory in the presidential election started a debate in the Labour party: should primaries be introduced for the selection of parliamentary candidates? But it was the Conservative party which capitalised on the idea with a series of successful primaries of their own. Now, a spate of local ballots in the leadership election has resurrected the idea in Labour circles.

Supporters of primaries in Britain tend to cite three arguments in their favour. First, they widen the pool of people who are able to seek elected office. The labyrinthine process of Labour selection can put off exceptional local individuals with a background in public service who share the party’s values, but who are not active members. Primaries can simplify the nominations process and allow people from a wider range of backgrounds to seek a career in politics. They may also result in candidates who are more representative of the local community.

The Conservative party’s primaries were a case in point. Local businesswoman Caroline Dinenage won in Gosport beating two party hacks – Sam Gyimah and James Bethell – in the process. Meanwhile, local doctors Sarah Wollaston and Phillip Lee won in Totnes and Bracknell respectively with the latter beating blogger and broadcaster Iain Dale, who had no local links.

Second, primaries encourage participation and civic engagement by opening up the selection process to a wider group of people. In safe seats, the choice of who may be MP for an extended period can be decided by fewer than 100 people. Research for Progress last year showed that, on average, just 40 party members voted in PPC selection contests. Primaries break through this stasis and force candidates to get organised early. Engaging a local electorate not once but twice during an electoral cycle is also good for democracy.

In Totnes, everyone on the electoral register was mailed a ballot paper and invited to take part in the selection of the Tory candidate. Close to a quarter of local residents responded as 8,000 voters got in the habit of putting a cross against Wollaston’s name. At the ensuing general election, the Conservatives more than doubled their majority against the Liberal Democrats.

Along the coast in Gosport, the primary turnout was a more modest 18 per cent but the added name recognition was enough to result in an astonishing 10.8 per cent swing against Labour as Dinenage trebled the Conservative majority. Notably, in the constituencies of Sleaford and North Hykeham, and Bracknell, where much smaller open selection meetings (known as caucuses) were conducted, there was a much more limited impact on the general election result. Although Labour was knocked into third place in both seats, the swing roughly reflected the national average.

Third, primaries can increase the accountability of MPs to the local community. In the US, members of Congress have to face primary elections even if they are incumbents. The necessity of winning these elections in the run up to a general election increases the importance of local representation. This both empowers the local community and reduces the power of the whips in parliament to bully through unpopular legislation.

It’s too early to determine whether the Conservatives’ ‘primary intake’ of 2010 will be more rebellious than their colleagues but after facing two local ballots rather than one, it’s easy to see why both Wollaston and Dinenage might feel more wedded to local concerns than to the party whip.

With all these apparent electoral advantages, why didn’t Labour experiment with a single primary in the run up to the May election? The main reason was money. When I put the case to party officials and the team writing the manifesto last summer, the question that came up again and again was cash. The Tories spent £38,000 a piece on the primaries in Totnes and Gosport. As the BBC pointed out, that equated to £3 per vote cast in the Hampshire town.

But the decision by John Mann to conduct a primary in his Bassetlaw constituency to determine how he should cast his vote in the Labour leadership election has shown that primaries can be organised for a little over £2,000. Instead of posting the ballot papers to residents, the main distribution was through hand- delivery by Labour volunteers as 15,000 local Labour voters received voting forms. The main cost came from the freepost service for the completed ballot papers but this was covered by an advert on the ballot paper and sponsorship from a trade union. The result, incidentally, was an overwhelming victory for David Miliband.

In Dudley North, the local Labour party is adopting the same approach but hopes to go one step further by including 30,000 local Labour supporters in its primary. MP Ian Austin nominated Ed Balls but writing for the Labour Uncut website said, ‘I’ve promised to cast the vote I’m given as a Labour MP for the candidate local people choose. It’s all part of our attempt to open up politics and maintain a constant conversation with the public.’

Also inspired by the Bassetlaw process, Edinburgh East’s new MP, Sheila Gilmore, decided to conduct a primary of her own. Gilmore had nominated Diane Abbott but only to ensure that the election had a wide field of candidates. Her agent, Kez Dugdale told me, ‘The Labour leader needs to command the support not just of Labour members, but of Labour-minded people in order to take on the Con-Dem government.’

Dugdale and her team hand-delivered 1,000 paper ballots to a cross-section of strong Labour voters that they had identified during the general election. But the process was also opened up online to any local residents on the electoral register who identified themselves as Labour supporters. ‘During the election we increased our contact rate from four per cent in the past to 34 per cent,’ says Dugdale. ‘We developed a culture of engaging with voters all the time and this primary was just an extension of that.’ A point proved recently when Gilmore was approached in a gay bar in Edinburgh where she was holding a surgery and asked, ‘Aren’t you the MP who’s doing the primary?’

The big question now is what to do on the back of these experiments. Mann suggests that they could be used in other elections: ‘We need to expand the use of primaries including for some MP selections and for councillor selections,’ he told me. The government’s coalition agreement pledged to fund 200 all-postal primaries over the course of this parliament. Labour is entitled to funding for 60 of these and the elections will be ‘targeted at seats which have not changed hands for many years’.

But scepticism remains. ‘I have a big debate with myself on whether to extend primaries to local candidate selection,’ says Dugdale. ‘We have to consider the rights and responsibilities of membership and picking candidates is one of the few things that a member still gets to do.’ Rod Pickford, secretary of Bassetlaw CLP, echoes this sentiment: ‘I can imagine people saying, “Why be a member if anyone can have their say?”‘

Perhaps that’s the point. Could the right balance in the future be to increase the role of members in areas such as campaigning and policymaking while giving the Labour-voting public more of a role in the selection of candidates? If the Conservative party’s experiences are anything to go by it could result in a significant electoral dividend.