A firework factory owner was convicted today of the manslaughter of two firemen killed in a massive explosion at his site.

Firefighter Geoff Wicker, 49, and support officer Brian Wembridge, 63, were killed in the blast at family-run Festival Fireworks UK Ltd at Marlie Farm in Shortgate, near Lewes, on December 3 2006.

Company owner Martin Winter, 52, was "grossly negligent" as he knew an unlicensed metal container packed with fireworks could explode if a blaze broke out.

As well as killing the two firemen, both long-serving members of East Sussex Fire and Rescue Service, the blast injured some 20 others, mainly police and fire officers.

Following a trial at Lewes Crown Court, the company, now called Alpha Fireworks Ltd, was also found guilty of two counts of breaching health and safety legislation.

The jury will continue its deliberations tomorrow on two charges of manslaughter faced by Winter's son Nathan, 25.

The victims

Brian Wembridge

Brian Wembridge, 63, married with two sons, had a long and distinguished career with the fire service, joining it as an operational firefighter in 1961. He retired in 1994, completing his service as officer in charge at Lewes, before transferring to support services where his role included taking footage at fire scenes. His images were seen in newspapers and on television and he was well-known for his enthusiasm for the fire service, according to bosses.

Geoff Wicker

Geoff Wicker, 49, married with two daughters, joined the fire service more than 30 years ago as a retained duty system firefighter at Mayfield, then switched to Heathfield, where he was watch commander. In the mid-1990s he joined the mobility and communication centre, and fire chiefs said his knowledge and skills saw him rapidly promoted to watch officer. Des Prichard, chief fire officer at East Sussex Fire and Rescue Service, described him as a "warm and generous person and highly respected for the dual roles" he played in the service.