The Conservative party is trying to use Monday’s TV leaders’ interviews as a chance to reboot its faltering election campaign with an online push focusing on Brexit and immigration.

Since Jeremy Corbyn and Theresa May faced questions from a studio audience and Jeremy Paxman, the Tories’ online operation has noticeably changed tack.

With the party’s poll lead narrowing, the phrase “strong and stable leadership” has gone, to be replaced by a relentless focus on leaving the EU and immigration.

Since the debate the Conservatives’ Twitter account has mentioned immigration 11 times and Brexit no fewer than 30 times.

The party has also paid for a Google advert that appears at the top of the page when users search for “Brexit”, “Theresa May” or “Jeremy Corbyn”.

Under the headline “The choice in this election: who will get the best Brexit deal for you?”it says: “Your vote at this election will decide who sits in the negotiating chair for Britain: Theresa May or Jeremy Corbyn … The outcome of these negotiations is central to everything … Control of our borders, our immigration levels and even our national security arrangements.”

A separate Tory advert on Google searches for the term “immigration” takes users to a page that attempts to capitalise on fears of foreigners taking British jobs.

It says: “When immigration is too fast and too high, ordinary working people pay the price. It puts pressure on people’s jobs, wages, and communities … Don’t risk letting Jeremy Corbyn run the Brexit negotiations – everything depends on getting Brexit right.”

The Brexit theme is echoed on the party’s Facebook page. “Tonight’s Sky/Channel 4 debate showed that only Theresa May can negotiate the best Brexit deal for Britain,” it says.

The foreign secretary, Boris Johnson, has been on message with the new approach. He was approvingly retweeted by the party after tweeting:

Only the PM can get the best Brexit deal #BattleForNumber10 — Boris Johnson (@BorisJohnson) May 29, 2017

The party has also continued to repeat the phrase “bloody difficult woman” as one of May’s virtues when it comes to negotiating with the EU. The same tactic was used on the eve of the party’s successful local election performance a few weeks ago.

Who do you want in charge of Brexit - Jeremy Corbyn or 'a bloody difficult woman'? #BattleForNumber10 pic.twitter.com/2NWVBrfPVH — Conservatives (@Conservatives) May 29, 2017

The Tories glossed over May’s difficulty answering Paxman’s question about why she had failed to meet previous manifesto commitments to reduce immigration to below 100,000 while she was home secretary.

Instead it has focused on Corbyn’s vague answers about immigration “probably” going down under a future Labour government.

Corbyn in the #BattleForNumber10 - won't commit to reducing immigration, won't commit to using Trident. Not fit to be Prime Minister. pic.twitter.com/EV3h11EE3y — Conservatives (@Conservatives) May 29, 2017

But clips of May’s performance on the debate have been noticeably absent from the party’s online activity.

By contrast, Team Corbyn and his supporters have been keen to promote edited highlights showing the Labour leader’s better moments in the debate.

Corbyn’s Twitter account carries a 90-second segment in which he tries to convince a reluctant Labour supporter that he is the man for the job.

The choice at this election is between @Conservatives who will deliver for the few & Labour who will deliver #ForTheMany. #BattleForNumber10 pic.twitter.com/nnsKNrehwB — Jeremy Corbyn (@jeremycorbyn) May 29, 2017

Momentum’s Facebook page selects a later exchange with the same voter when Corbyn portrayed himself as a leader willing to listen. “To me, leadership is as much about using this [pointing to his ear] as using this [pointing to his mouth],” Corbyn said.

Momentum also liked the part when Corbyn batted away a question from Paxman about why Labour’s manifesto does not include a segment about getting rid of the monarchy. It clips Corbyn saying: “There is nothing in there [about getting rid of the monarchy] because we are not going to do it.” The clip then features an approving superimposed animation showing Corbyn in shades smoking a spliff.

Labour supporters, or in the case of the former footballer Stan Collymore opponents of May, have been keen to highlight the reaction of a man in the audience to the prime minister’s defence of government spending on the NHS.

The man could been seen mouthing: “Bollocks, utter bollocks”.

“Bollocks man” as he has become known, now enjoys cult-hero status.