LONDON: Campaigners for a British exit from the European Union are expressing anger at US President Barack Obama's call for the UK to stay in the bloc. In an article for the Daily Telegraph newspaper, Obama says the EU 'enhances Britain's global leadership.' UK Independence Party leader Nigel Farage says Obama — who is due to meet Prime Minister David Cameron later Friday — should 'butt out.' London Mayor Boris Johnson, a leader of the exit campaign, said Americans 'would never contemplate anything like the EU for themselves.' Writing in The Sun newspaper, Johnson said Obama's stance 'is a breathtaking example of the principle of do as I say, not as I do.'