Image caption Reg Race is behind the group campaigning against Jeremy Corbyn

For months a campaign to oust Jeremy Corbyn has been placing adverts, collecting data and imploring people to vote against him in Labour's leadership election.

Look on the Saving Labour website, though, and you won't find the name of a leader. There is nothing on the register of limited companies either.

When you learn who is co-ordinating the project, it comes as a surprise.

A former MP on Labour's far left, once active in a socialist pressure group that included Mr Corbyn himself, Reg Race is not the first person you would imagine leading the charge for a more centrist party. But he is deadly serious.

"We are ruthlessly determined to make sure there is an effective opposition in this country," he says.

He claims Saving Labour has been responsible for recruiting more than 120,000 registered supporters and affiliated union members to vote against Mr Corbyn using online advertising.

The group, he says, has amassed details of 60,000 people on its own database in just two months. There are plenty of numbers, rather fewer names.

In his first broadcast interview, he told Radio 4's Today programme he has the support of trade unionists but will not say which ones. Nor does he name any MPs. Nor donors; those will be published by the Electoral Commission in time, he says.

Why the secrecy?

"There's a group of us and lots of us don't want to be out there in terms of the media because they're in relatively vulnerable positions," he says.

Online campaigning

Mr Race's own history is written in the newspaper archives. In 1990 the Independent reported that he established a group called Labour Party Socialists alongside Mr Corbyn and the late Tony Benn.

A Guardian report from the previous year quotes him explaining - as a member of an organising committee - why Sinn Fein MP Gerry Adams had been invited to speak at a socialist conference, at a time when Mr Adams' voice could not be legally broadcast.

He was trying, he says now, to engage with Mr Adams to urge him to persuade the IRA to stop killing people.

Since then he has set up and retired from a private firm that conducts surveys for the NHS. His views, he says, have changed.

On the face of it, Saving Labour has a pretty simple purpose. In the leadership election of 2015, Mr Corbyn's online campaigning trumped his rivals, and it continues with the work of his current campaign and his supporters' group Momentum. Those rivals do not want to make the same mistake twice.

"Data is absolutely crucial in these races," says Tom Flynn, Saving Labour's full-time digital campaigner. "This was set up as a way of trying to get good data on those Labour people who would like a change of leadership."

That data - the contact details of sympathisers who have a vote in Labour contests - could have an interesting future.

A Saving Labour supporter, MP Graham Jones, suggests it may even play a part in trying to get rid of Unite's general secretary Len McCluskey.

"As I understand it from conversations that, yes, it would want to try and get involved in making moderate progressive views heard throughout the movement and that may be in the Unite general secretary's election," he says.

Huge task

That would be an inflammatory intervention in Labour politics, and Mr Race is clear it certainly is not his intention.

When you consider the full-time digital guru and the ads, though, the unanswered question about funding plays in the mind. It is clear at least that there is money for political campaigns by those who see life differently from Mr Corbyn.

A separate group called Labour Tomorrow boasts the former cabinet minister Lord Blunkett among its directors and the former Liberal Democrat peer Matthew Oakeshott among funders who have donated more than a quarter-of-a-million pounds in a couple of months.

Overturning the Corbyn lead in the leadership contest, a lead suggested by a recent YouGov survey whose results and methodology Mr Race disputes, would be a huge task.

But the data, the money and the intent of those trying to wrestle back control of the Labour Party from Mr Corbyn will not expire at the declaration of the result.

If they fail this year, they will try again.