The LTA has set a target to attract new, young players with emphasis (and funding) being put into "Kids Zones". There are 3 recommended sizes - RED/ORANGE/GREEN (dimensions can be found in FAQS - "Sizes").
Ideally, a Kids Zone should have -
A brightly painted (red and blue) 12m x 6m Mini Tennis Court with red and blue 'halves' for coaching purposes.