A peak audience of 19.19m (71.6%) were tuned in to ITV1 at 9.50pm to see dance act Diversity crowned the surprise winners over long-time favourite Susan Boyle. The ratings figure is thought to be the highest ever peak for a reality TV programme in the UK.
Overall, the 30-minute results programme averaged a huge 17.33m (67.6%) for ITV between 9.30pm and 10pm.
The earlier Talent show, which saw the ten finalists take to the stage to give their performances, averaged out to 15.32m (71%) between 6.45pm and 8.30pm. A peak audience of 18.02m (75%) were watching at 8.10pm.
ITV2's spinoff show Britain's Got More Talent also benefited from the buzz surrounding finale night. A pre-results programme, shown between 8.30pm and 9.30pm, picked up 1.64m (8.3%), then the post-results show averaged 2.37m (13.5%) from 10pm. The channel's coverage peaked with 3.09m (15.6%) at 10.05pm.
In between the two Talent shows on ITV1, celebrity gameshow All Star Mr & Mrs had a predictably strong performance, averaging 7.3m (33.1%). Straight after the Talent final, new comedy Mumbai Calling launched to a decent 4.88m (23.4%).
ITV1's average primetime share was a colossal 49.2%, while ITV2 averaged 5.4%.
BBC One took a huge hit opposite the competition last night, dropping to an average audience share of just 10.5%.
Robin Hood logged its lowest ever audience at 7.25pm, with just 1.94m (8.5%) tuning in over 45 minutes. The Lottery draws followed with 1.59m (6.7%), then Casualty grew the audience to an evening high of 4.34m (19.7%).
BBC Two was mostly unaffected last night, with 2.01m (9.1%) tuning in for a Dad's Army repeat at 8.30pm. Documentary Bloody Omaha, about the D-Day landing in Normandy, put in 1.64m (6.9%) in the 9pm hour, then an extended version of Have I Got News For You appealed to 2.77m (13.5%). The channel averaged an overall share of 7.1%.
Five attracted audiences of 799k (3.5%) and 1.1m (4.6%) for NCIS from 8pm, then a new episode of CSI: NY brought in 1.89m (9.6%). Law & Order closed off prime for Five with 924k (8.2%). Overall, Five averaged out to a 5% share.
Channel 4 was last among the terrestrials, averaging a share of 3.5% (+1: 0.3%) for its night of Hitler-themed programming. The Hitler Family, about the evil dictator's efforts to hide his family, interested 934k (4.1%) in the 8pm hour. The concluding half of Hitler - The Rise Of Evil followed with 921k (4.2%) over two hours.
Ratings data supplied by Attentional