Westpac's FX Strategist Sean Callow notes that in a setback for the ‘stay’ campaign, London mayor Boris Johnson declared his support for Brexit. Key Quotes "Over the weekend, UK prime minister Cameron reached agreement with the EU on further concessions to support ongoing UK membership of the EU and announced 23 June as the date for a referendum on whether the UK should stay in." "In a setback for the ‘stay’ campaign, London mayor Boris Johnson declared his support for the ‘leave’ campaign. GBP/USD had risen into the weekend, from 1.4270 to 1.4400 and reversed this move early Monday." For more information, read our latest forex news.