Momentum is attempting to lead a sophisticated campaign operation for Labour by combining traditional doorstep conversations with bespoke websites, a few borrowed ideas from the US and innovative use of WhatsApp.

In just two weeks, the leftwing campaign group has raised £330,000 – more than its entire budget for the 2017 election – mobilised thousands of activists and deployed a range of technological tools to try to help elect Jeremy Corbyn as prime minister. With more than 40,000 members, it’s also expanded from 13 paid staff to 56 for this election campaign.

“This is a once-in-a-generation chance to change the country,” said Joe Todd, Momentum’s head of communications.

Since it was founded in 2015 by Jon Lansman, Emma Rees, Adam Klug and James Schneider – the latter now head of strategic communications for Corbyn – Momentum has undergone a transformation from grassroots campaigning to influencing policy at party conferences, especially on green and education issues.

While critics have dismissed it as a Corbyn fan group, Laura Parker, the group’s national coordinator, said Momentum “has always been about politics” and claimed its growing sway on policy “really shows the power and potential of politics from below”.

In 2017 staff from the Bernie Sanders campaign in the US ran training courses for volunteers, and these continue this year, teaching campaigners how to have “persuasive conversations” on the doorstep.

Momentum “unseat” events targeting Boris Johnson in Uxbridge, Iain Duncan Smith in Chingford and Amber Rudd in Hastings have drawn hundreds of volunteers in the last 12 months.

But what is strikingly different this election is the group’s turbo-charged digital strategy. The UniVote website, which coders set up a month ago, shows students where is the most advantageous place to cast their vote.

Momentum’s online election tools include UniVote and My Campaign Map. Photograph: Linda Nylind/The Guardian

Another website, My Nearest Marginal, which cost £30 to set up in 2017 and was key in getting canvassers to significant constituencies, has been revamped for this campaign. It is now My Campaign Map and has had 750,000 hits. Colour-coded events are uploaded daily by volunteers.

The “Labour legends” programme asks people to take a week’s holiday from work to campaign. So far 1,078 people have signed up, providing 40,000 volunteer hours.

All of this is run from a shabby office in Finsbury Park, north London. Past a hallway strewn with bikes, a small nucleus of 20 to 30-somethings were glued to laptops and working to shape the Labour campaign. There was a hum of activity and excitement. A whiteboard spelled out a daily plan and messages such as “real change” were written on the walls. At one of end of the room a digital team worked on making videos for social media. One on Brexit uploaded a few hours earlier had already been viewed 150,000 times.

Todd said: “Lots of these things haven’t been done in the UK before. Someone knocking on your door is great but really people need to get mobilised by their friends and family. If you go around this office, most people have been politicised through their friendship networks.”

The Tories are not known for their dynamic or innovative use of social media in elections but they are making much more of a concerted effort this time. They have hired Australian social media experts who helped elect Scott Morrison as PM. Last week the party released a “12 questions” video with Boris Johnson, which served as a social media party political broadcast and was shared widely. Johnson has also done live Q&As on Facebook, a significant step forward from Theresa May’s limited use of social media.

Momentum has looked to the Bernie Sanders campaign’s adoption of ‘distributed organising’. Photograph: Linda Nylind/The Guardian

In contrast, Momentum looked to the Sanders campaign’s adoption of “distributed organising”. This method creates a network that allows a huge number of people to participate by distributing knowledge and resources.

Momentum’s paid “distributed organisers” oversee the work of the various volunteer teams: data entry, research, calling voters, video clipping, a support team and translation, which converts material into seven languages including Urdu and Arabic.

“You can’t say ‘this is huge’ and then ask people to knock on doors for an hour or two. You have to give them a bigger responsibility, like organising events rather than just attending them,” said Todd.

The clipping team scan hours of news footage taking the best clips for the campaign – good ones of Labour politicians and bad ones of Tories and Lib Dems – and packaging them for social media. Staff have said a significant number of carers and night-shift workers – people who can’t get out on the doorsteps – contribute to this part of the campaign effort.

WhatsApp is used to run “Let’s Go” teams. Within three days of signing up, campaigners are invited to join a WhatsApp group and take part in a phone-in where they can find out how to run events like phone-bank sessions from their living room.

Jan Baykara, 25, a software engineer, said he wanted to use his digital skills to help Labour. “I realised I had some niche skills I could offer and that with some facilitation you can have influence as an everyday person. I want to live in a nice country. My mum is disabled, my partner is an immigrant. It means a lot to me that we win.”

He said the digital side could feel abstract, so it was important to share experiences. “We are making tech, but we are making tech so people can relate to each other and live in a more caring country, which is definitely possible.”