The garden bridge, proposed to cross the Thames from the South Bank to Temple, is nothing if not a landmark of the post-truth era. It has wrung tens of millions out of the public purse on the basis of deceptions, distortions and facts that proved to be fake. First sold as “a gift to the people of London”, entirely paid for by private sector donations, it is now due to cost a minimum of £60m in public money. Its estimated total cost has gone from £60m to “north of £200 million”. Its claims to fundraising prowess are exaggerated, its promised transport benefits minimal.