What does the Worcester Bosch Flame detected after gas fault code mean?

Your boiler thinks it can still see a flame even though it has told the gas to turn off, which is causing it to shut down for safety.

Worcester Bosch Flame detected after gas Fault Code: What It Means & How to Fix It

Typical repair cost for the Worcester Bosch Flame detected after gas fault is £150-450 including labour.

Cables and connections to gas valve. Gas valve switched off. Condensate trap. Flue (for blockages). Otherwise replace control board.

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.