The 74-year-old was the guest of honour at the hall on Saturday afternoon, the first in a series of question and answer sessions organised by the Welsh Lib Dems.
Members of the public got a glimpse of life in the coalition, and managed to learn a little about what Mr Cable thinks of his main political rivals.
WATCH footage of Mr Cable's speech here:
But the point of the meeting, he said, was to get back to basics – speaking with residents about the issues they face, and what the Lib Dems could do to help.
“We didn’t know who was going to be here,” he said.
“We expected a fair number of ‘antis’, but obviously we have a lot of supporters in Welshpool.
“Westminster is a bubble. It’s where all the politicians, lobbyists and media are, and it is a bit of an echo chamber. Actually getting out and meeting a wide variety of people, many of whom are struggling at the minute, is a very important part of my job.
“It’s only a matter of time before we come back in Montgomeryshire. It was a Lib Dem stronghold – we will be back.”
Mr Cable started his speech on Brexit, and it was a theme that continued throughout the hour-long Q&A.
Some audience members wondered if the issue shouldn’t be sorted out in parliament, while others asked whether another referendum should be held.
And although he admitted he was usually against referendums, Mr Cable said the country had already set out on that road and that any decisions needed to be made by the people.
He believes that a second referendum would turn around the decision to leave the EU.
'On the facts'
“The split between leave and remain hasn’t changed very much,” he said. “It’s moved a little bit towards people who think leaving is a bad idea, but it’s not shifted a great deal. If they were to set for another vote, this time on the facts, it will be for about Christmas time. I think once people are clearer about what Brexit means, a lot of the negatives that were not really brought out in the last campaign, I think we will stay.
“I don’t mean that the EU is wonderful. I think there’s a big movement at the moment that needs a different kind of Europe, not just the status quo.”
He said that completely cutting ties with the EU without having a deal in place, as suggested by Nigel Farage, would be disastrous for the country. He was confident, however, that Prime Minister Theresa May wasn’t considering it.
Pressures on the NHS need to be fixed, Mr Cable said. And although part of the issue could be fixed in Government, another part needed to be changing attitudes towards when to go to A&E.
He said that visiting a hospital for help with a bad cold was “ridiculous”, despite it happening all the time.
Travelling long distances to get to hospital was never a good thing, he added. “There is a tendency on the part of the NHS to deal with pressures by cutting costs,” he said. “It takes very little account on the pressure of patient’s families who need to travel backwards and forwards.
Mr Cable said that many Labour politicians were feeling lost in the “hard left” Jeremy Corbyn party.
But he did give Shropshire-born Corbyn one bit of credit – for his use of social media during the last General Election campaign.