BBC One's evening coverage of Team GB's gold-medal rush pulled in an average of 12.22m (51.4%) between 6.50pm and 10.10pm.
Jessica Ennis's heptathlon win logged a high of 16.3m at 9pm, while Greg Rutherford's long jump victory grabbed 15.6m at 9.25pm.
The figures, which combine BBC One and BBC Olympics HD, do not account for crowds watching in pubs and on big screens.
BBC Three's rolling coverage managed a peak of 3.5m (32.8%) at 1pm, capping a record-breaking day for the digital channel.
BBC Three's all-day share of 7.9% was second only to BBC One, which averaged a huge 42.4%.
BARB ratings data supplied by Attentional