A spokesman for East Sussex Fire and Rescue Service said: “CCTV footage has been reviewed as part of the investigation and we can confirm the cause was accidental and fireworks were not involved.”

Western Road was temporarily closed on Thursday night to allow emergency vehicles to reach the restaurant, but it later reopened.

A spokesperson for Wendy’s said: “Our thoughts are with those recovering from this incident at our Brighton restaurant.

“The safety of our customers and employees is our top priority.”