Late 60s at Shawbury, back when the helicopters were still flying at Tern Hill, the based flying units were UBAS and 8 AEF flying Chipmunks, and Marshall's Vampires and Piston Provosts, which were used as training targets for the baby ATCOs, learning their trade at the Central Air Traffic Control School. Shawbury at that time was no longer a Master Diversion Airtield, so the only itinerant traffic consisted of occasional Gnats and Hunters from Valley, practicing PARs and diversions plus aircraft coming to 27 MU, mainly for scrapping.
One day I was flying a Chipmunk with an instructor to the west of Shawbury. Unless we were going to do instrument approaches, we always stayed on the Local (Tower) frequency. We heard a Hunter T8 from Valley on the frequency and it was obvious that the student had a poor command of English and was having trouble understanding the ATC instructions. My instructor, Brian N, was intrigued and when the Hunter went around and was passed back to Approach, he switched to Approach as well, without bothering to tell the Local controller. During the vectoring for the next approach, the controller starts giving headings to the Hunter, to steer around a target at "unknown altitude". The penny dropped and we looked up to see the Hunter several thousand feet higher, making a dog-leg around us!
A quick switch back to Local and we heard the controller calling us, complaining that he hadn't been able to reach us. We didn't confess!