Jon Ashworth has recommended the Labour Party learn the lessons of positive campaigning, “owning change” and tackling separatism from Justin Trudeau’s Liberal party.

The victors in the Canadian election brought alive the promises of investment rather than austerity and attacked Labour’s sister party the New Democratic Party (NDP) from the left, Ashworth writes in a pamphlet for Policy Network.

The former Gordon Brown advisor said Labour must learn how to build a progressive alliance which reached out to different groups and embrace what Trudeau calls “sunny ways” when communicating with the electorate.

The party should prioritise rebuilding in Scotland according to Ashworth, who says that the threat of separatism holds back marginal voters in English town who worry a weak Government would be beholden to the SNP.

Ashworth, who is currently in the shadow cabinet, also lauded the data work of the Canadian Liberals, saying Labour’s 2015 ground operation, in which the party had more than 5 million conversations on the doorstep were held back by poor polling that gave us too high expectations.

“The absolute priority for all of us in the Labour party is to put our time, effort and energy into building again an election-winning coalition,” Ashworth writes,

“To do that, it is very much worth understanding the lessons from Canada about positioning, campaign process and policy.

“Justin Trudeau attacked the NDP apparently from the left – committing the Liberals to run annual deficits until 2019/20 to fund $125bn on infrastructure – while simultaneously offering an olive branch to Conservative voters he described as ‘neighbours not enemies

“But positioning matters too. Announcing the deficit policy Trudeau said ‘this election is a clear choice between smart investments that create jobs and growth, or austerity and cuts that will slow our economy further.’

“But rather than going heavy on evermore shrill anti austerity rhetoric, the Liberals calmly explained what the extra borrowing would pay for. Trudeau brought alive the ambition of the infrastructure pledge, talking not just of spending billions but of connecting Canadian cities while supporting the middle class with a targeted tax cut and raising taxes on the richest.”

Ashworth heralded Labour’s current “catastrophic” polling, saying it provided the impetus to consider Trudeau’s methods. Theresa May has ruled out an early general election, but many consider a 2017 election possible given the Conservatives’ high levels of support.