Underneath the now rapidly disappearing layer of bitumen on the WW2 runway at RAF Upottery, Devon, numerous letters followed by what appeared to be dates are seen in the attached photos on the concrete slabs which form the runways. I believe, using the common sense principle, that the letters relate to the initials of the Foreman in charge of the gang laying the concrete and the date refers to when it was laid. Building the runways was such a staggered process that the slabs were laid over several weeks and so dried at different rates. I find this absolutely fascinating. I believe it was the 680 General Construction Company-Royal Engineers that constructed Upottery amongst several other airfields. I am off to the National Archives at the end of the month as they hold some war diaries relating to this unit for around the right time period in 1943/44. I'm hoping this may even reveal the names behind the initials. Two questions for the members though please: 1) Have any of you seen similar markings on WW2 runways before and, if so, where? (I've not spoken to anyone who has just yet, my belief is that these are a rare sight?) 2) The last photo is one of several similar concrete slabs with four holes in them. They are situated in the middle of the runways at various points.....are these a post-war addition and does anyone know what their use was? Many thanks in anticipation!