Bishop's stand-up show, airing between 9.20pm and 9.50pm, climbed 300k week-on-week to an average of 4.09m (19.8%) for BBC One.
Ronnie Corbett's Comedy Britain, despite being heavily publicised all week, amused just 3.09m (14.9%) in the 9pm hour, adding a further 218k on ITV1 +1.
With the likes of John Cleese, Matt Lucas, Miranda Hart and Stephen Merchant all making contributions, what renders the two-part show's low ratings all the more surprising is the strong lead-in from the channel's screening of the fourth Harry Potter film.
Harry Potter and the Goblet of Fire pulled in a highly respectable 5.33m (27.5%) between 6.10pm and 9pm (+1: 546k), ahead of Tonight's The Night's 3.56m (19.2%) at 6.40pm, The National Lottery: In It To Win It's 4.85m (23.6%) and Casualty's 5.23m (24.4%) for BBC One.
Channel 4's showing of The Battle of Britain interested 1.31m (6.6%) between 6.30pm and 9pm (+1: 155k), then 1.1m (5.3%) tuned in for Camelot. Watchmen, the movie based on Alan Moore's graphic novel, secured 1.1m (9.2%) from 10pm.
Over on BBC Two, Dad's Army roused 1.61m (8.2%) at 7.30pm, after which The Impressionists and Proms coverage interested 881k (4.1%) and 725k (3.7%).
Meanwhile, Law & Order (7.30pm), CSI: NY (8.30pm) and Law & Order: SVU (9.15pm) brought in audiences of 513k (2.6%), 756k (3.5%) and 1.37m (6.8%).
Overall, BBC One beat ITV1 in primetime with 20.8% against 20.1% (+1: 2.2%). Channel 4 claimed third place with 6.9% (+1: 0.6%), followed by BBC Two's 4.9% and Channel 5's 4.2%.
BARB ratings data supplied by Attentional