POLICE are hunting two gangs of robbers who carried out raids at petrol stations in Essex - including one in which a member of staff was tied up.A robber armed with a handgun held up a lone member of staff at the BP garage in Baddow Road, Chelmsford, on Wednesday night.

POLICE are hunting two gangs of robbers who carried out raids at petrol stations in Essex - including one in which a member of staff was tied up.

A robber armed with a handgun held up a lone member of staff at the BP garage in Baddow Road, Chelmsford, on Wednesday night.

The garage worker, a man in his late teens, was alone in the shop when three men entered at about 10.10pm.

They tied him up by putting tape around his wrists, ripped out the CCTV and tried unsuccessfully to open the safe. They stole a small amount of cash from the till trays, a large box of cigarettes and some electricity cards.

The robbers then fled in a car, which possibly had alloy wheels.

The member of staff managed to partially free himself and bang on the window of the shop. Police were alerted and a member of public who heard the banging also came to the man's aid.

Yesterday police issued descriptions of the robbers. The gunman was white, aged 25, 6ft 3ins tall and skinny. He wore a black hooded top with the hood up and small white Nike logo on the left hand side.

The other robbers were also white and about 25-years-old. One was medium build and wore a hooded top with the hood up.

The second robbery took place at the Sainsbury petrol station in Coggeshall Road, Braintree, yesterday .

A van driver was delivering to the petrol station at about 7.50am when a blue H-registration Ford Granada Scorpio pulled up behind and three men, one black, two white, got out.

They started taking grey plastic bags out of the delivery van and loading them into the car. The delivery driver, a 52-year-old from Suffolk, tried to intervene and was punched in the face and pushed to the ground by the black man.

The delivery driver ran into the shop to call police. He did not require hospital treatment.

The raiders got away with about £500 of cigarettes, tobacco and cigars.

The black robber is described as 6ft tall, aged between 18 to 25, with an African accent. He wore dark blue jeans, a light green jacket and red baseball cap. His accomplices were a similar height and age, but a smaller build.

Police would like to hear from anyone who witnessed the robbery or saw the car before or afterwards. Anyone with information should contact Braintree CID on 01376 551312.

Detectives investigating the armed robbery in Chelmsford would like to hear from witnesses on 01245 491212.