Voters in the home counties will “regret it for a long time” if they do not back the Liberal Democrats and wake up to a Reform-led council, Ed Davey has said.

The Lib Dems leader has identified five councils – East Surrey, West Surrey, Hampshire, West Sussex and Huntingdonshire – where his party could win overall control, as well as swathes of the former “blue wall” where Davey said it was a “straight fight” between his party and Reform at the English local elections.

More than 5,000 councillors will be elected on Thursday, with more than half of these being in either London or the south-east. Some projections show the Lib Dems gaining 500 seats, with Labour losing as many as 1,800. The Greens are also expected to gain hundreds of seats, with top projections putting the figure at 1,700. The pollsters More In Common expect the Lib Dems to take the newly created East and West Surrey councils.

“If we are going to stop Reform, we are the party most capable of doing that, it is on a knife edge in some of these areas,” Davey said. “People could vote Labour or Green and then we will get narrowly beaten by Reform and people will regret it for a long time.”

Unlike previous elections, Labour and the Conservatives have a fractured voter base, putting many seats up for grabs for the Greens, Liberal Democrats and Reform.

Davey said the Lib Dems were a better bet than the Greens, adding: “We are finding that when people realise the choice is us or Reform, lots of people who were even thinking of voting Conservative were coming to us, certainly Labour and Green are coming to us. Tactical voting will be key, Reform is working really hard, spending lots of their money, meaning results will be on a knife edge.”

He said that in parts of the north of England polling showed a straight fight between the Lib Dems and Reform, including Stockport and Hull, and that areas such as Portsmouth in the south should consider voting Green to stop Reform. “I am determined we stop them now,” he said.

A lack of opposition to Donald Trump and weakness over the war in Iran had hurt the chances of Reform and the Conservatives, he said, adding that it was a mistake for the Tory leader, Kemi Badenoch, to have tacked so hard to the right.

“When you talk to that traditional one-nation, pro-Europe liberal Tory, they are pretty upset with Kemi Badenoch; they feel the Conservative party has left them,” he said. “They look at us and see us standing up for Britain against Trump’s bullying, they like what we are saying on the economy and defence, and they feel more comfortable with us.”

The Lib Dems were well placed to take these areas because, he said, unlike Labour and the Greens, they could convince disillusioned Tories to give them their vote. “There is a big difference between us and the Greens,” he said. “The Greens are basically taking votes from Labour. We are taking votes off the Tories to stop Farage. I don’t think the Greens are going to play much role in stopping Reform, whereas we are literally central.”

He said his party had been fighting hard on local issues, including fly tipping, potholes and sewage pollution in rivers. Davey also plans to campaign to reduce the price of a pint after it was reported that it had hit £10 in some parts of London.

“I like a pint like everyone else and the idea of £10 a pint should make people think twice,” he said. As well as proposing to cut national insurance tax for employers if the Lib Dems were elected to government, “we would look at cutting VAT for hospitality as well”.

But more broadly, he said he had noticed the US president come up in conversations on the doorstep. “He is coming up all over the place, people will talk about potholes and then they will go on to Trump in the same conversation. The vast majority of people detest Donald Trump and they associate Nigel Farage as being Trump’s champion; he recently referred to Trump as the ‘boss in Mar-a-Lago’.”

Davey reiterated that people who do not want “Trump-style policies” should vote tactically, including voting Liberal Democrat in areas where they were polling second behind Reform.

“The fact Farage was cheerleading for Donald Trump and calling for us to get into the war has angered many,” he said. “Progressive voters obviously can’t stand Trump, but even Tory voters and some Reform voters [can’t either] if they have seen that Farage wants to bring Trump-style policies to the UK.”