Can anyone identify this very dimly remembered time-travel story?

This is a real long shot, and I’ll be amazed if the Dope can come up with an answer, but then the Dope has amazed me plenty of times before!

I dimly recall reading a book when I was a kid, in probably the late 1980s. It might have been a short story in a collection rather than a standalone novel. The plot revolved around some kind of time-slip to (I think) WWII-era London, from the then-present day, say mid-1980s. I also seem to remember the Thames Barrier, which was new at the time, featuring.

I think the main character was a young, maybe teenage, boy, and I’m pretty sure it was a children’s/teenagers’ book.

And for some reason I remember the main character repeating like a mantra “Today is Tuesday February 12, 1986” (or whatever the “real” date was) in an attempt to somehow hang onto reality when the time-slip happened.

Does this ring any bells?

Might have been Terry Pratchett’s Johnny and the Bomb, but I think that’s a bit newer than your timeframe.

I’m pretty sure it wasn’t Pratchett. I didn’t discover any of his stuff till quite a bit later, and it wasn’t that kind of style.

Just a little bump for today’s crowd.

Well, I’ve come across Time to go back / by Mabel Esther Allan. It’s early 70s though and the teenager is female. Description: A rebellious teen-ager goes back in time to Liverpool during World War II and views her own mother’s adolescence and her aunt’s tragic romance.

A popular plot. London calling / Ed Bloor. This is pretty new. Description: Seventh-grader Martin Conway believes that his life is monotonous and dull until the night the antique radio he uses as a night-light transports him to the bombing of London in 1940.