By Ali Lyon For the first time in at least two decades not a single new office scheme smaller than 100,000 square feet began construction in London in the first half of this year, despite demand for larger spaces reaching record highs. Data from property analytics firm CoStar, shared exclusively with City A.M., has revealed there to be just 1.1m sq. ft. office space under construction in smaller buildings, the lowest for over ten years and almost 40 per cent below the 10-year average. But the dearth of new small offices in the capital lies in stark contrast to new starts of larger working spac…