Nigel Farage's 'terrible' back and shoulder pain has forced him to cut his working day and consider quitting smoking. The UKIP leader said the pain meant he was not 'firing on all cylinders' during the early weeks of the election campaign, but insists he is now 'back on form'. He revealed he was suffering after a flare-up of an old spinal injury and had been prescribed Temazepam, a strong sleeping pill and muscle relaxant. Scroll down for video . Quitting: Mr Farage said 'terrible' back and shoulder pain has forced him to cut his working day and consider ditching cigarettes . Mr Farage is known for having a cigarette in his hand but was pictured smoking an e-cigarette yesterday . The party leader admitted he had not been following his doctor's orders to the letter, leaving him seeming under par in the opening weeks of UKIP's campaign . Mr Farage has been dogged by speculation that he was ill during the run up to the General Election but he insists he is not unwell. The 51-year-old told the Daily Telegraph he has been receiving private hospital treatment in London and had been prescribed the sleeping drug Temazepam. He claims campaigning has not left him with enough time to attend NHS appointments. Certain things can make people become more at risk of developing back pain, including smoking. The increase in risk  may be because smoking has caused tissue damage in the back or because smokers tend to have unhealthier lifestyles than those who don't smoke. Source: NHS . 'I was not unwell, I have not had heart palpitations, but I was getting increasingly terrible pain in my shoulder, my back, and so I was suffering from neuralgic pain,' he told the newspaper. 'I am taking a few tablets but it is something I have got to live with, and I have got to pace myself. I think I am going to have medical treatment for the rest of my life.' Mr Farage said he has cut his working day to 14 hours and may give up smoking. He was pictured smoking an e-cigarette yesterday. When asked by BBC's Newsnight earlier this week whether he was 'operating at 100%', Mr Farage said: 'To be honest with you, in the earlier part of the campaign I wasn't, and I wasn't feeling quite as sharp and as fit as I should have been.' However, he blamed it on getting his 'diary planning wrong' and said he was now feeling 'pretty bouncy'. Mr Farage was injured in a plane crash on the day of the 2010 General Election, suffering broken ribs and other minor injuries . Mr Farage revealed he was suffering after a flare-up of an old spinal injury and had been prescribed Temazepam, a strong sleeping pill and muscle relaxant . The party leader admitted he had not been following his doctor's orders to the letter, leaving him seeming under par in the opening weeks of UKIP's campaign. He told BBC News: 'I've not been doing physio. I've not been doing my exercises. 'I've been so obsessed with the UKIP campaign that I put myself into a position where I wasn't really firing on all cylinders.' Mr Farage was injured in a plane crash on the day of the 2010 General Election, suffering broken ribs and other minor injuries.
Nigel Farage is considering quitting smoking because of 'terrible' back pain . UKIP leader wasn't 'firing on all cylinders' at the start of election campaign . Suffering from flare-up of spinal injury and been prescribed sleeping pills .