Gordon Brown has told Labour supporters not to “lose courage” as the party continued to face the fallout from the leak of its election manifesto.

Brown told the party to “fight” for its values as he delivered a 25-minute speech which did not make any reference to Jeremy Corbyn.

The former prime minister was speaking in Coventry where called for jobs and the manufacturing industry to be the priority when Britain goes to the polls in four weeks’ time.

He made his first big intervention of the general election campaign as John McDonnell – the man who tried and failed to win a place against him in the leadership ballot in 2007 – defended the draft manifesto as a “transformational” vision.

Today Brown spoke out about the risk to the economy from Brexit but also delivered an impassioned plea to the left to stand up for industry, families and the NHS.

“You can be up in 1997 and down by the 2010s,” he said, in comments reported by the BBC.

“You can be the darlings of the media, as Labour was for some time, and yet the very same media is now telling you, you’re the enemies of the people. So yes, politics goes in cycles.

“The test, however, is what you do in the difficult times. It’s that you don’t lose the courage to fight for what you believe in, you don’t stand back and say ‘this is now not for me, it’s too difficult’, but you continue to fight and support and champion what really matters to the future of this country.”

“It is our duty to show this country that there is a better way forward.”

Brown, who stood down from the Commons at the last election, was prime minister from 2007 to 2010. He sought to shift the focus of the election on to the economic challenges over Brexit.

Polls show voters who backed Leave and Remain want tariff-free and tax free trade with Europe, Brown said.

“Jobs must be on the ballot paper – our industrial economy must be on ballot paper, the future of manufacturing must be on ballot paper and the prospects for young people must be on the ballot paper….

“The Conservative government has so far put tariff-free access to the European Union secondary to their other objectives.

“The case for tariff-free, tax-free, friction-free access to European markets cannot be parked or ignored: as the British people constantly say the case for manufacturing and the car industry must be put forward.”