Some 22.94m - a share of 80.7% - were tuned in to BBC One alone between 9pm and 12.15am. An average of 202k (0.7%) watched on BBC Olympics 1.
Copyright: Tony Marshall/PA Wire/Press Association ImagesFigures - that don't account for those watching in pubs and on outdoor big screens - didn't once drop below the 20m mark during the live event.
The 'Symphony of British Music' - which featured appearances from the likes of the Spice Girls, The Who, One Direction and Ray Davies - was nearly as popular as the 27m-scoring opening ceremony just over two weeks ago.
However, a closer look at Sunday's ratings also indicate that around a million viewers switched off during George Michael's set between 10.15pm and 10.30pm - denting the overall average.
Gary Lineker and Sue Barker's Closing Ceremony build-up attracted 12.3m (49.7%) from 7.30pm, meaning BBC One claimed a huge primetime win with 65.8% - the same share it garnered on the night of the Opening Ceremony.
But as the BBC celebrated, ITV suffered the worst ever day in its 57-year history - averaging just 673k (2.1%) for a two-hour repeat of A Touch of Frost from 9pm. Overall, ITV1 averaged a 3.9% (+1: 0.3%) share in primetime.
Setting a new all-time low for the third time in the series, the penultimate episode of Channel 5's Big Brother took 483k (1.5%), eclipsed by BBC Two's The Dark: Nature's Nighttime World (521k1/6%).
Elsewhere, Thelma's Gypsy Girls held 722k (2.2%) and 150k (0.5%), as Channel 4 took a very low 2.2% (+1: 0.3%) peak time share.
Meanwhile on the multichannels, Ricky Gervais's appearance on Family Guy amused 518k (1.6%) at 10pm, and The Only Way Is Essex logged just 416k (1.3%) for ITV2 at 10pm (+1: 100k/0.4%).
BARB ratings data supplied by Attentional