London is exactly 1 hour behind Madrid year-round. When it's 3:00 PM in Madrid, it's 2:00 PM in London. Both cities observe daylight saving time on the same schedule.
Interestingly, Spain uses Central European Time despite being geographically aligned with the UK. This dates back to 1940 when Franco changed Spain's timezone to align with Germany. London uses GMT/BST.
Any business hours work great! With only a 1-hour difference, 9:00 AM - 5:00 PM London corresponds to 10:00 AM - 6:00 PM Madrid. Full business day overlap.
London and Madrid are connected by numerous daily flights (2.5 hours). Post-Brexit, Madrid has attracted some financial services relocating from London while maintaining strong business ties.