Police are providing emergency security to a Bradford pie company after a series of violent armed robberies.

A bakery worker from the Crusty Pie Company was hit with a hammer, tied up and sprayed in the face with bleach in the latest raid at the company's premises in Stanage Lane, Shelf, on Monday.

The robbers escaped with a substantial amount of cash. Detectives were interviewing the victim today.

The raid followed two armed robberies, in July and December, at the home of the bakery company boss in Thornton, Bradford.

The masked gang are also thought to be responsible for two other armed robberies, one at the home of the boss of another Bradford bakery.

Police have advised bosses at the Crusty Pie Company to install CCTV cameras and panic alarms at both the business premises and their home, and have temporarily offered police alarms for their protection.

Detective Inspector Ash Hewitt, of Calderdale CID, said: "These are dangerous men who need catching. I am not going to discount this could happen again, but we are taking every step to ensure it doesn't.

"I am confident from descriptions that these are young people who will have suddenly come into a large amount of cash and be bragging about it. Someone in the local community must know something about who has done this."

One of the suspects is believed to be aged 17 or 18, another is in his early 20s. All three are thought to be white. Two are 5ft 10-11ins and the third 5ft 6-7ins.

Anyone with information is asked to contact Calderdale CID on (01422) 337085, or Crimestoppers, anonymously, on 0800 555 111.