Royal Mail bosses have been forced to stop using street mail boxes in parts of Bradford because they are being raided by a gang.

About 1,000 items of post have been stolen from 'bag boxes' - used to store mail for postal workers to collect on their rounds - in Girlington, Heaton and Manningham.

The raids began two days before Christmas and the latest was on a box in Saplin Street, Girlington, this week.

It is believed the thieves rifle letters for money or anything they can cash in, with birthday cards particular targets.

Now the Royal Mail has suspended the use of the bag boxes in the areas affected and is having to take on extra staff so that mail can be delivered directly to the post workers on the streets.

A Royal Mail spokesman said it was suspected that the gang watched for postal vans to deliver mail to the bag boxes and then pounced before the postmen collected it.

"They might even have followed vans," the spokesman added. "They know they have a limited time to break into the boxes, but if they have a vehicle they can be in them with a jemmy in a matter of moments and be away in the car in ten or twenty seconds.

"They are after anything that has value they can realise cash with. Birthday cards are an obvious target.

"There can only be a very few items of any value, but it is a great inconvenience to us. We have had to put extra resources into delivering bags of mail directly to postmen on the road. It is a logistical nightmare because people are scheduled for other duties.

"Postmen are doing overtime and extra staff have been taken on temporarily to have the manpower to do the job. But the integrity of the mail is paramount."

He apologised to customers who had suffered as a result of the thefts and added: "Royal Mail has taken measures to ensure the mail is protected."

He appealed for any householders or shopkeepers who could help by safely storing mail to come forward.

"We do use premises, like shops, as safe drops and in view of the current situation we would be very interested to hear from any customer or member of the public living in the areas who would be willing to provide safe drop facilities.

"They may have a shed with a spare key that we could use to put our mail in, or we have specialist padlocked boxes we can put at the back of properties. We pay £25 a year for the service."

The spokesman said that a member of the public had reported seeing a box break in to police and provided them with a description of the suspect and a vehicle they were using.

He added: "We would be delighted if anyone with information about these thefts contacted the police and helped us catch the thieves."

Inspector Angus Rushton, of Bradford North Police, said they had received 11 reports of thefts of mail since Christmas Eve.

"It is an issue that has arisen over the last few weeks," he said. "We have had a number of break ins from boxes in those areas. They are clearly on the lookout for cash or cheques.

"Someone was seen breaking into one and we despatched officers, but we didn't catch them. The problem is it only takes seconds to break in and get away."

Insp Rushton confirmed a vehicle had been spotted at one recent incident and police were following up positive lines of inquiry.

He urged the public to be vigilant and asked for anyone with information to contact the help desk at Lawcroft House police station on (01274) 376259.