Nigel Farage's controversial claim that foreign nationals with HIV should not be treated on the NHS was part of what insiders called a ‘shock and awful’ strategy. A Ukip source revealed the party had initially planned for Mr Farage to mention the number of foreign patients suffering from tuberculosis, in the leaders debates last night. But when it was discovered that the antiretroviral drugs to treat people with HIV were more expensive, a decision was taken to use that example instead. Scroll down for video . Nigel Farage's controversial claim that foreign nationals with HIV should not be treated on the NHS was part of what insiders called a ‘shock and awful’ strategy . Mr Farage was greeted with silence in the hall when he said during the debate about the NHs that of the 7,000 diagnosed with HIV, 60 per cent were born abroad. After saying this was something the other leaders would be ‘mortified that I dare to even talk about it’, he said: ‘You can come to Britain from anywhere in the world and get diagnosed with HIV and get the retroviral drugs that cost up to £25,000 per year per patient. ‘I know there are some horrible things happening in many parts of the world, but what we need is to put the National Health Service there for the British people and families who have paid into this system for decades.’ Despite criticism from other parties and viewers, Ukip revealed it had been part of a deliberate strategy to appeal to their ‘core voter’ – not to try and attract floating voters to the party. A Ukip insider said Mr Farage’s remark was ‘a bit spicy’. They added: ‘We were going to go for TB but we found out that the HIV drugs were more expensive’. The strategy, it was claimed, was ‘shock and awe, or as some would call it shock and awful.’ Mr Farage was greeted with silence in the hall when he said during the debate about the NHs that of the 7,000 diagnosed with HIV, 60 per cent were born abroad . It comes after Ukip’s share of the vote in recent polls has dropped significantly from highs of 19pc late last year, to just 10pc in several polls over the past month, as supporters appear to have returned to the Conservatives and Labour. Mr Farage has claimed he would stand down if he does not win the seat he is contesting in Thanet South, and last night all of his answers focused on the need to curb immigration. Ukip first MP Douglas Carswell refused to endorse Mr Farage’s remark. Asked several times whether he agreed with it, he said Mr Farage had given ‘credible’ answers in the debate. Douglas Carswell has refused to endorse Mr Farage's remarks . Mr Carswell, the MP for Clacton in Essex, added: ‘It is sensible and reasonable to say we want a national health service, not an international health service, and that’s all I’m going to say.’ George Osborne, the Chancellor, said the remarks were intended to provoke a reaction from ministers and said ‘I’m not going to dignify them with a response’. A half-time poll from ComRes/ITV News poll showed 24 per cent of voters giving Mr Farage the lead in the debate, but almost as many thought he was also the worst of the seven leaders. Jo Swinson, the Liberal Democrat business minister, said the remarks were ‘breathtakingly appalling’. Mr Carswell’s father, Wilson, was a respected physician and fellow of the Royal College of Surgeons who diagnosed the first confirmed cases of HIV in Uganda in the 1970s. He was the inspiration for the character of Dr Nicholas Garrigan in The Last King of Scotland. Mr Carswell yesterday insisted the party was not split. He said: ‘I see what you’re trying to do in asking me this slanted question. I thought Nigel was superb in the debates. His answers were credible.’ Mr Farage appeared to embarrass Mr Carswell when he won his seat in a by-election in October by calling for a ban on people with HIV entering the UK. Mr Carswell said at the time: ‘I think this row has been slightly confected. Noone is seriously suggesting we should screen people for HIV coming in.’
Ukip leader said foreigners with HIV should not be treated on the NHS .
Mr Farage had planned to mention foreign patients suffering from TB .
He chose HIV after discovering NHS drugs to treat disease more expensive .