To be somewhat more do-able, this prospective TV channel wouldn't air well-known series like Doctor Who (which currently airs on Retro TV and BBC America, among other places), The Avengers (which currently airs on COZI TV) or those currently airing on PBS (like Doc Martin and Downton Abbey).
But there's a wealth of vintage programming that could be aired instead, some of which may not have aired in the U.S. before (where I'm based), or even released on DVD.
To get started, here's what a lineup for the first day of the channel's (which I'm calling "Brit TV" for short) debut, could look like, accompanied by YouTube links to the episodes where available.
Thursday, November 12, 2015:
6:00am: Classic BLUE PETER
Two vintage episodes of the BBC children's program.
7:00am: TIMESLIP
First episode of series: "Wrong End of Time" part 1 (orig. aired Sept. 28, 1970)
7:30am: WORZEL GUMMIDGE
First episode of series: "Worzel's Washing Day" (orig. aired Feb. 25, 1979)
8:00am: FOLLYFOOT
First episode: "Dora" (orig. aired June 28, 1971)
8:30am: THE BLACK ARROW
First episode: "The Prophecy" (orig. aired Dec. 4, 1972)
9:00am: COUNTRY DIARY OF AN EDWARDIAN LADY
Episode 1 (of 12): "January" (orig. aired Feb. 22, 1984)
9:30am: THE DISTRICT NURSE
First episode of series. Orig. aired Jan. 10, 1984.
10:00am: THE RIVALS OF SHERLOCK HOLMES
First episode: "A Message from the Deep Sea" (orig. aired Sept. 20, 1971)
11:00am: LILLIE
Episode 1 (of 13): "Emillie" (orig. aired Sept. 24, 1978)
12:00pm (noon): UPSTAIRS DOWNSTAIRS
First episode of series: "On Trial" (orig. aired Oct. 10, 1971)
1:00pm: Classic CORONATION STREET
1:30pm: Classic EASTENDERS
First episode of series (orig. aired Feb. 19, 1985)
2:00pm: Classic EMMERDALE
2:30pm: EMMERDALE (new episode)
3:00pm: EASTENDERS (new episode)
3:30pm: CORONATION STREET (new episode)
4:00pm: HEARTBEAT
First episode: "Changing Places" (orig. aired April 10, 1992)
5:00pm: ME AND MY GIRL
Sitcom. First episode of series (orig. aired Aug. 31, 1984)
5:30pm: FREDDIE & MAX
Sitcom. Episode 1 (of 6). Orig. aired Nov. 12, 1990.
6:00pm: AGATHA CHRISTIE HOUR
Episode 1 (of 10): "The Case of the Middle-Aged Wife" (orig. aired Sept. 7, 1982)
7:00pm: ADVENTURES OF SHERLOCK HOLMES (Jeremy Brett series)
First episode of series: "A Scandal in Bohemia" (orig. aired April 24, 1984)
8:00pm: HOUSE OF ELIOTT
First episode of series. Orig. aired August 31, 1991.
9:00pm: IN SEARCH OF THE TROJAN WAR
Documentary, hosted by Michael Wood. Episode 1 (of 6): "The Age of Heroes" (orig. aired Feb. 24, 1985)
10:00pm: BLAKE'S 7
First episode: "The Way Back" (orig. aired Jan. 2, 1978)
11:00pm: THRILLER
First episode: "Lady Killer" (orig. aired April 14, 1973)
(Episode runs 1 hour, 8 minutes. With commercials, it would fit a 90-minute time slot.)
12:30am: DANGER MAN
First episode: "View from the Villa" (orig. aired Sept. 11, 1960)
1:00am: UPSTAIRS DOWNSTAIRS (repeat of 12pm episode)
2:00am: LILLIE (repeat of 11:00am episode)
3:00am: CORONATION STREET (repeat of 3:30pm episode)
3:30am: EASTENDERS (repeat of 3:00pm episode)
4:00am: EMMERDALE (repeat of 2:30pm episode)
4:30am: Classic EMMERDALE (repeat of 2:00pm episode)
5:00am: Classic CORONATION STREET (repeat of 1:00pm episode)
5:30am: Classic EASTENDERS (repeat of 1:30pm episode)
First episode of series (orig. aired Feb. 19, 1985)