What causes low engine compression in UK cars?

Low engine compression in UK cars is typically caused by worn piston rings, cylinder wall damage, or faulty valve/spark plug seals. The most common issues include: 1. Worn piston rings (particularly in older vehicles like the Vauxhall Corsa or Ford Focus) where oil control becomes less effective; 2. Scored cylinder walls from carbon buildup or foreign objects - a problem that can affect popular diesel models like the Volkswagen Golf; 3. Leaking valve seats or spark plug threads (especially in aluminium cylinder heads found in modern MINIs and Jaguars) often caused by over-tightening during servicing. For accurate diagnosis, UK drivers should consult a qualified mechanic or use a compression tester, available at Halfords or other automotive retailers.