Shadow Cabinet minister Jonathan Ashworth has warned Labour against becoming a party of protest and told the Left to find answers to the rise of right-wing populism of Europe and the US.

Ashworth, shadow minister without portfolio, told Labour’s sister party in Canada that a changing global economy demanded different ways to boost social justice and living standards and said there had “never been a greater need” for a spirit of internationalism.

The Leicester South MP also attacked the ambitions and record of George Osborne, a likely future Tory leadership candidate, who has borrowed more money than any chancellor in British history.

Ashworth told the New Democratic Party convention that increasing populism was changing the tone of politics.

“The challenge for those on the left in the UK, Canada, Europe and the US is to channel this anger into the politics of answers, not just anger.

“Our joint mission is to ensure unhappiness with the status quo turns people to progressive politics, not the anger of right wing reactionary populism.

“It requires the construction of a new progressive policy agenda for new times with answers on the economy, social justice and how to make globalisation work for the many, not the few. This is the shared challenge for our times. This is the shared challenge for our parties.”

Ashworth, a former advisor to Gordon Brown, is in Canada to represent Labour at the New Democratic Party (NDP) convention in Edmonton.

He will also travel to Ottawa to meet politicians and strategists from the NDP as well as from the Canadian Liberal Party, led by Justin Trudeau, the prime minister.

Trudeau’s Liberals won the Canadian election in October last year with 39.5 per cent of the vote, having come from third position in the polls.

Ashworth also attacked the UK Conservatives for a series of privatisations – which included the cut-price sale of Royal Mail – and their failure over the jobs crisis in the steel industry, as well as over David Cameron’s days of denials over the Panama Papers scandal.

“In the UK we know about Tories. We have a Mr [Oliver] Letwin the policy guru who cut his teeth in Canada advising Tories on privatisation even writing a book called Privatising the World, it was hardly a best seller, we have Business Secretary [Sajid Javid] asleep at the wheel, incompetent in his approach to our steel jobs crisis, we have a Chancellor, George Osborne, desperate to be the successor [to Cameron] but has broken every promise on the debt, cutting taxes for the richest while cutting support for the poorest and those on middle incomes, and has overseen the biggest current account deficit since the Duke Of Wellington.

“And now we have a Prime Minister who after several days of ducking and diving has finally been forced to admit did hold shares in a fund now linked to tax avoidance. In the past he called this behaviour ‘morally wrong’, let me assure you Tories always think it’s one rule for them and another for the rest.

“Well we in the Labour Party will not this Tory Prime Minister get away with it.”