Detectives today said that a gang of robbers may be staging armed ambushes on businessmen, attacking as their victims arrive home from work.

Senior detectives are studying similarities between two hold-ups in the Bradford area, both of which saw gunshots fired, one hitting a restaurant owner in the foot.

And now officers are speaking to colleagues across the district and beyond to see if they form a wider spate of offences.

The first incident happened last Wednesday as a 49-year-old shopkeeper pulled up outside his home in Moore Avenue, Great Horton, at about 8.25pm.

As the man and his 21-year-old son climbed out of their van, they were confronted by three masked men who demanded cash.

The pair - who believe they may have been followed back from the Bradshaw area of Halifax - grappled with the attackers, but one of them pulled out a handgun and fired it through the windscreen before grabbing a gold bracelet.

The robbers then jumped into a silver Vauxhall Vectra and sped away.

Then, at around 12.30am on Saturday, a Bradford restaurant owner was ambushed as he arrived at home in Hinchcliffe Avenue, Baildon.

As his car pulled to a halt, an Asian man forced the door open, produced a handgun and demanded cash. After the 50-year-old dad handed over money, he was shot in the foot. He has since had parts of his foot amputated.

The robber jumped into an awaiting silver Vauxhall Vectra - with part registration N671 - thought to contain two accomplices.

Det Supt Geoff Dodd of Bradford South CID - which covers the Great Horton area - said: "We are looking carefully at these two offences to see if they are linked. "Obviously, we will also study any offences which have taken place which show any similarities."

Detective Chief Superintendent Roger Gasson said: "We are looking at all offences of a similar nature. I will be speaking to other crime managers in the Bradford and Halifax areas."

A police spokesman said that another robbery in which a shopkeeper was attacked at 2.45am yesterday by his home in Park View Road, Heaton, was not being linked at the moment.

The 30-year-old man was threatened by two men - one with a handgun and the other with a knife - as he returned home at 2.50am yesterday.

Cash and a leather jacket were taken and the victim suffered minor injuries. The first attacker was described as Asian, 6ft tall, of medium build, wearing dark clothing. The second was Asian, 5ft tall, stocky, with very short, dark hair. They made off in a dark coloured car, possibly driven by another man.

Anyone with information on any of these offences, or the silver Vauxhall Vectra, should contact 0845 6060606 or Crimestoppers on 0800 555 111.