Nigel Farage has said he would prefer immigrants from India and Australia to eastern Europeans, despite previously claiming that his party would not want to discriminate against new arrivals by nationality. The Ukip leader indicated that he would prefer immigration from countries he said had the most similar cultures to the UK as he was grilled about his approach to immigration during the latest BBC Leader interview broadcast on Wednesday evening.

Asked by presenter Evan Davis whether he would favour immigrants from some countries over others, he said: “I have to confess I do have a slight preference. I do think, naturally, that people from India and Australia are in some ways more likely to speak English, understand common law and have a connection with this country than some people that come perhaps from countries that haven’t fully recovered from being behind the iron curtain.”

In the past, Farage has always claimed to be the only party leader with a “non-discriminatory” policy on immigration as Ukip would not give preference to EU migrants over those from the rest of the world. Last year, he told LBC: “I actually want us to have an immigration policy that is non-discriminatory, because at the moment we discriminate in favour of people from Poland, or Romania, or Bulgaria, regardless [of] who they are, and we discriminate against people from New Zealand … or from India, or Canada, or whatever else it may be. We’ve got our, I think, our priorities completely wrong here. And we should not be discriminating on grounds of nationality.”

The Ukip leader also suggested that his party has sometimes used heightened rhetoric about immigration to get noticed. Asked about his desire to stop more immigrants with HIV and criminal records coming to the UK, he said such language was sometimes necessary “to wake people up”. “To wake people up to the truth of what’s going on, you sometimes have to say things in a way to get noticed, of that there’s no question,” he said.

Farage claimed Ukip was now fighting this general election campaign without a negative tone and “no longer needs to make the negative arguments about the effect that immigration has had on primary school places, on healthcare provision, on wage compression”.

However, Farage has mentioned the impact of immigration on public services many times during the campaign, including stressing that it would be wrong to fund the treatment of immigrants with HIV when the country cannot afford drugs for an 80-year-old with breast cancer. He brought up the issue of immigrants with life-threatening diseases unprompted during the first leaders’ debate.

He also criticised Davis’s questioning, accusing him of being a member of the “liberal metropolitan elite”.

Two more Farage interviews are being aired on Wednesday evening, on ITV and Channel 4, as Ukip gets more prominence from broadcasters since being designated a major party.

In a candid exchange with Channel 4 News, the Ukip leader revealed he made some mistakes at the beginning of the general election campaign. The politician has been under pressure as opinion polls suggest support for his party is sliding to below 14% and that he is facing a tight three-way battle to win the seat of South Thanet.

And Farage said that he had tried to do too much. “I started the campaign and think I made some mistakes,” he told Channel 4. “My desperation for Ukip to do well meant that I really packed the diary and the day in a way that frankly wasn’t very bright. I have now trimmed it back a bit. I’m being a bit more selective.”

Asked whether he had got a bit “wonky” at one point, Farage said: “I was. No, no. Hands up, I was. I had completely overdone it. I wasn’t getting it right. I feel a bit of the old vim and vigour back and I’m looking forward to the next fortnight.”

The Ukip leader strongly denied rumours about his ill-health at the party’s spring conference in Margate, Kent, accusing the Tories of spreading false claims about him and claiming to be “fit as a flea”.

However, since then, he published an autobiographical book, Purple Revolution, saying several health scares – including testicular cancer, a car crash and a light aircraft crash – have left him with the body of a 70-year-old.

David Cameron, meanwhile, has also been accused of looking like he is lacking enthusiasm during the campaign. The prime minister hit back at his critics on Wednesday by saying he has visited 26 places in less than a week.

Farage’s campaign has concentrated in a much smaller area than some of the other party leaders, as he tries to win his own target seat of South Thanet in Kent. He has pledged to stand down as leader if he does not become an MP.