Sketch: Red Eds woo blue collars

It's a windy, rainy day on an industrial estate on the outskirts of Stevenage in late November. We are halfway through the first fixed five-year parliament, and Ed Miliband and Ed Balls are playing the long game. They're looking forward to next week's autumn statement, and have come to a factory to explain their views to a group of bemused-looking staff.

Actually, these sorts of visits offer plenty of excitement. They are a break from the monotony of the working day. So for the crowd of 100 or so factory workers at Propak Sheet Metal in Stevenage, the arrival of two Eds is an occasion ripe with opportunity for amusement.

"What do you think of Ed Miliband?" I ask one or two of the factory workers standing near me, as we wait for the leader of Her Majesty's opposition to turn up. Long silences follow. They don't trust politicians, it's clear. They're actually thoroughly preoccupied worrying about a drip in the factory roof, which they seemed convinced will begin to deluge itself down in exactly the place Miliband was expected to stand.

When Miliband and Balls do turn up and begin speaking, it's not the rain that proves the problem. It's the wind. A loud banging repeatedly interrupts Miliband's opening remarks. It sounds like the office boy has decided to skip the event and kick a football against the wall to pass the time.  "There isn't – BANG! – enough work – BANG! – for people to do," Miliband says, carrying on gamely. Balls, characteristically, addresses the issue head-on. "The wind and weather is battering the whole of Britain, and it's battering the building here today," he says charmingly. An appropriate metaphor for the state of the economy, perhaps, but on this occasion he passes up the opportunity to make it.

Balls' presence seems to help Miliband, in that he is able to delegate any question remotely related to education to his "former education secretary". The shadow chancellor is the chirpier of the two, during the Q&A session at least. His hand is in his pocket and his eyes are sparkling away as he explains exactly what is so good about his policies in government, and so bad about the coalition's. Miliband seems struck by the gravity of Balls' comments when in listening mode, but warms up as the event goes on and by the end had got his audience laughing here and there.

The questions are starting to dry up, so Miliband wraps up with another little speech before taking a final round of applause. I turn to my right. "He's changed my mind," the factory worker declares. I'm impressed." And all those nearby seem to be nodding their heads. Worth the trip, then.

After a few interviews in the office upstairs the two Eds pose with Labour's candidate in Stevenage, a nice lady called Sharon, and the factory's senior staff for a picture or two. Balls is worried by one of the banners behind, which trumpets Propak's defence contractor work by stating 'MILITARY' in big letters. They take the photo anyway. After some cruel words about my moustache – neither Miliband nor Balls think my Movember effort should survive beyond December 1st, and make it clear in no uncertain terms – they depart.

What about 'the guvnor'? After the Labour caravan has finally left I grab a word with the boss, a silver-haired man called Bruce. He doesn't want to come across as selfish, he says, but it can be taken as read that he's in the top income tax band and isn't happy at the 45p rate. So much for the tax cuts for millionaires rhetoric of Miliband, then, who would have preferred Bruce to continue to be taxed at 50p. "I've got my own views," he says staunchly. He's not with Labour on the right approach to deficit reduction, either. "Get the pain over fast," he urges. The men on the factory floor might have been swayed, but Bruce hasn't budged an inch.

You might be wondering: what about that banging noise? It turned out that the problem was caused by a fan, high up on the ceiling, out of anyone's reach, which was being blown around by the weather. Out of anyone's control, they explained. A bit like the economy.