The BBC’s respected Laura Kuenssberg, uncharacteristically, made a serious mistake when she asked the first question to Jeremy Corbyn after he launched the Labour Party’s election campaign in Battersea yesterday.

Was there much difference, she inquired, between Corbyn’s launch now and the launch of his campaign in 2017?

Well, there is. The major difference between March 2017 and Halloween 2019 is that in 2017 Jeremy Corbyn was happy to go with the Brexit flow and strongly distanced Labour from any idea of challenging or confirming the referendum result once we had a Brexit deal.

Instead Labour devised its own policy of six tests that the Government would have to meet for Labour to approve Mrs May’s Brexit withdrawal proposals. None of those tests included consulting the people.

Yesterday, in a Copernican revolution, Corbyn announced he was committed to a new referendum, the People’s Vote, which has been the principal demand of pro-European groups in the last two years.

Corbyn even used the phrase “Trust the People” first coined by the 19th century Tory Prime Minister, Benjamin Disraeli.

In his speech Corbyn said: “We need to take it (Brexit) out of the hands of the politicians and trust the people to have a final say.”

For a life-long professional politician to claim Brexit should be taken out of the hands of the politicians was pure chutzpah. Yet it shows how far Corbyn had travelled under pressure from his MPs, Labour Party members, and the millions of Labour voters who switched to the LibDems or Greens, notably in the 2019 EU election, in protest to his refusal, until very recently, to back a new referendum.

Corbyn grandly announced that three months after entering Downing Street he would re-negotiate a new deal with the EU and that within six months both a new Brexit deal and the option simply to remain in the EU would be on the ballot paper.

There were similar processes in Denmark and Ireland after initial referendum decisions to repudiate EU Treaty membership were then followed by second referendums which kept Ireland and Denmark in Europe.

It is still far too early to see if Corbyn can win enough seats or at least win more than Boris Johnson and then possibly form a coalition with other parties - all of which support a People’s Vote.

What is clear is that Labour is now fighting the 2019 election as the party of a new referendum on Brexit and that is a significant political development.

The Labour Party conference adopted this policy in September and Corbyn has been paying lip service to it ever since. But many cynical Corbyn watchers thought he might wriggle out of the commitment.

This hasn’t happened. Labour is now the party of a new referendum on Brexit. It allows a 2 for 1 offer. Vote Labour and if a Labour supporter you can have all your favourite left policies AND you can have a People’s Vote, a second referendum on Brexit.

It has taken a long time but now Labour is looking down the barrel of a general election it has decided that allowing the people a vote on Europe is a good idea.

In fact, the only parties with MPs in the Commons who still oppose a People’s Vote are the Conservatives and the DUP. Might they change before voters run to LibDems, the SNP, the Greens and now Labour, all of whom back a People’s Vote?

By Denis MacShane - former Labour Party MP for Rotherham and former Minister of State for Europe.