A jewellery shop owner today told of his guilt after his father was robbed at gunpoint of £100,000 of gems as he looked after his business.

Mohammed Umer, 31, revealed that he is now offering a £5,000 reward for information leading to the arrest and conviction of the callous armed robbers.

The gang used a stolen car to smash their way through the front window of the shop, Shaandar Zewar jewellers in Maidstone Street, Bradford Moor, on March 8.

Four masked men burst into the shop and two of them threatened Mr Umer’s father, Mohammed Bashir, 63, and staff member Shazad Ishaq, 29, with firearms before making off.

Mr Umer, who was on a two-day business trip to Hong Kong at the time of the robbery, said: “I feel really guilty that I put my dad in this position. It should have been me.

“It was a terrifying experience for both of them and has had a big impact on dad. He still can’t sleep three weeks after it happened. He has become quieter and is afraid in his own home. It may always be with him.

“In the past, when I have been away on business or holiday, my dad has looked after the shop. That will never happen again.”

Mr Umer said the robbery had ruined the lives of his family but pledged that he would continue with the business and this week re-opened the shop after relatives helped to pay for the £12,000 repairs.

He said he was offering the reward because he did not want such a robbery to happen to anyone else.

“It’s vital that these people are caught,” said Mr Umer. “They are going to kill someone. They rammed the car into our shop and didn’t care if anyone got hurt.

“At first I just wanted to give up the business and when I re-opened I was really scared. But my family are very supportive and I am determined not to let the robbers drive me out.”

The suspects used two stolen cars in the robbery – a Ford Focus and a black Volkswagen Golf GTi, bearing the registration MJ55 YBT.

Detective Inspector Ian Bryar, of Bradford South CID, said: “We hope the reward will encourage somebody with significant information to come forward to the police as soon as possible. “We know that two of the offenders had firearms and those guns were pointed at Mr Bashir and members of the public outside.”

Anyone with information about the robbery is asked to call police on 0845 6060606, or Crimestoppers, anonymously, on 0800 555 111.