Most local plumbers in London prioritize emergency calls and aim to respond as quickly as possible. Typically, you can expect a plumber to arrive within 1-2 hours for urgent issues like burst pipes or severe leaks. However, response times may vary depending on the time of day, location, and current workload. It's always best to have the contact information of a reliable 24/7 emergency plumber on hand to ensure prompt assistance when you need it most.