The crescent visibility map below for Ramadan 1439 shows that moon will be born on 15 May 2018 at 11:48 GMT/UT, but it may not be visible by the naked-eye anywhere in the UK/Morocco region on that date. However, on 16 May 2018 the moon will be easily visible in the UK and in most countries of the world. (Lunar parameters at London sunset: Moon Age: 32 hrs, Alt: 9°. Elong: 19°, lag: 69 mins.) Hence, the month of Ramadan will start from 17 May 2018, InShaAllah.