Using environmental tracers to evaluate the preservation of palaeoclimate signals in aquifers of the London Basin, UK

•14C ages from dissolved organic carbon (DOC) in 30 chalk and sandstone groundwaters.•DOC ages resolve problems with dissolved inorganic carbon (DIC) reservoir effects.•Sandstone noble gas recharge temperatures agree with climate changes back to 24 kyr.•CFCs indicate man-made contamination reaching over 40 km from chalk aquifer outcrop.