Graham Mills, 73, who lives on Alderdale Avenue, Sedgley, Dudley, where the PM went campaigning on Saturday morning, said he was 'really disappointed' with the PM's performance – and even refused her permission to walk on his lawn.
He quizzed her on privatisation, her refusal to take part in leadership debates and her 'poor' record as home secretary.
But despite his barrage of questions, Mr Mills claims he never got straight answers.
The pair had got off on a sour foot anyway when Mrs May was refused permission to walk across Mr Mills's lawn, as he explained: "I was cutting my grass at the time when I saw a load of cars pull up and she came towards me.
Sources suggest long-serving local councillor Eddie Hughes is now the Conservative frontrunner to challenge Labour veteran David Winnick in Walsall North.
He is a former member of the police authority and chairman of Walsall Housing Group.
Previously, it had been thought that Douglas Hansen-Luke was being lined up for a second run at the seat, after narrowly losing in 2015.
However, a Conservative insider told the Express & Star last night: "We need a strong, locally-known candidate, as opposed to someone largely unknown or who has failed in the past.
"With someone of Eddie's calibre among us, why would we look anywhere else?"
"First of all she asked if she could walk across my lawn and I said no, not really, I have just cut it.
"I started by asking her why she would not debate the other leaders on the TV and she said 'well we meet every Wednesday' and I said that is hardly an answer and asked if she thought she owed it to the public. Again I did not really get an answer.
"I asked her why she was running the exact same campaign as David Cameron did with Lynton Crosby and employing the same scare tactics by suggesting Labour would form a coalition with the SNP, which she knows they wouldn't. It is scare tactics.
"I was amazed at how nervous she was.
"She spoke about Europe saying we had to get things back so I asked her why doesn't she start at home
"She kept giving me stock answers every time – which was that it would be worse under Labour. I was really disappointed."
May's Black Country battle cry
Theresa May later said the Black Country is a 'very important battleground' ahead of the 'most important election' of her lifetime.
The Conservatives are looking to snatch seats away from Jeremy Corbyn's Labour in Dudley, Walsall and Wolverhampton at June's General Election and have earmarked Walsall North, Dudley North and Wolverhampton South West as key targets.
Alderdale Avenue, where Mr Mills met Theresa May, is in Dudley North, which Labour MP Ian Austin fought hard to defend at the last election. In 2010 he had a majority of just 1.1 per cent.
It is also on the border of Wolverhampton South West, which has swung between the main parties in the past two elections.
Labour had just a two per cent majority at the last general election and the Conservatives are hopeful of overturning that, especially after current MP Rob Marris announced last week he would not be seeking re-election.
Speaking at Netherton Conservative Club on Saturday, Mrs May said: "The Black Country is very important and is going to be a very important battleground for the next election.
"Every vote that is cast here is going to be important for the future of our country. It will be a vote for a stronger Britain in the future."
PM under fire after dodging tax issue
Theresa May has been under fire after refusing to rule out tax rises during her visit to Dudley.
The Prime Minister repeatedly refused to rule out the possibility of raising taxes but insisted the Conservatives remain the party of 'lower taxes'.
The controversial prospect, believed to be the work of Chancellor Phillip Hammond, saw the Tories face a setback in the polls.
Mr Hammond has hinted he would like to drop the promise of no tax rises because it restricts his options for dealing with Brexit.
Following the news, a Survation poll put the Conservatives on 40 per cent, followed by Labour on 29 per cent and the Lib Dems and Ukip on 11 per cent each.
It means Mrs May's lead over Jeremy Corbyn has nearly halved in four days – with some potential Tory voters also angry that she is refusing to step back from David Cameron's huge overseas aid commitment.
Mrs May was three times offered the chance by journalists to make it clear her party would not be raising taxes – something it pledged for the last General Election – but declined to give a straight answer each time.
Labour shadow chancellor John McDonnell said the Conservatives were planning a 'tax bombshell' if returned to power while Liberal Democrat former business secretary Sir Vince Cable claimed Mrs May was 'at war' with her chancellor over the issue of taxation.
Mrs May and her Conservatives have a commanding 20-point lead over Labour in the opinion polls but the PM insisted she and her party are not complacent and would 'be fighting for every single vote'.