A blue sign with the following text.
For; Birmingham; use; A42 (M42); at junction 23A.
We're about to meet the A38, which goes to Birmingham and for many years was the main road from here to the West Midlands. In 1991, the M42/A42 route was completed, and this sign was put here to encourage Birmingham-bound drivers to stay on the M1 a bit longer to use it.