Last updated at 18:46 02 July 2007

The BBC has been branded 'insensitive' and 'mad' after staging a giant explosion in a crowded city centre, just hours after the latest terror attacks.

Shocked shoppers feared terrorists had struck again when the blast rocked streets during filming for Dr Who spin-off series Torchwood.

Police only issued an alert on the day of the explosion, meaning many shoppers were completely unaware of the plans and thought they had been the latest city to be targeted by Islamic extremists after London and Glasgow.

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Members of the public vented their fury at the ill-judged decision to carry on with the explosion next to the Millennium Stadium in Cardiff just yards from the busy shopping streets, restaurants and bars in the Welsh capital on Sunday evening.

They became alarmed when the blast happened in an old courtroom building which sent a huge pall of smoke over the city centre.

Father-of-three Pete Humphries, 47, said: "The BBC must be mad doing this now. It was loud and frightening. It is incredibly insensitive. My blood ran cold when I heard that bang."

Mum-of-two Amanda Thomas, 34, said: "I jumped out of my skin. It was a huge bang - and I thought of terrorism straight away.

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"You'd think the police might have stopped the BBC doing it after what's happened over the last few days with terrorism. They've targeted London and Glasgow so any major city might be next."

Her mum Brenda Protheroe, 59, said: "What an earth were the BBC thinking of doing this now - couldn't it have waited a couple of weeks."

The BBC issued their own warning on local radio and online on the same day of the blast. But it was too late for many of the frightened shoppers.

It was due to have two blasts two hours apart but cut it to one after the security alert.

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Police sent uniformed officers to calm people passing and the BBC has their own private security teams on stand-by.

Inspector Andy Walbeoff, of South Wales Police, said: "We decided to issue the warning to the public because of the heightened state of alert following the other incidents.

"It was short notice because of the change of events but we realised some people would be frightened We didn't want people running away thinking they were real bombs going off.

"We watched the explosion from our control rooms on our cameras and it seemed to make a mighty bang."

Huge cannons sent papers into the street, a pall of smoke went out and stunt people were seen rolling around in agony.

The filming was for new Torchwood series starring John Barrowman due to be screened later this year.

A BBC production team insider said: "The filming was planned many weeks ago before the recent terrorist incidents.

"We had informed neighbouring businesses but could not tell everyone who might be in the city centre. We apologise if anyone was frightened."

A BBC spokesman said that controlled explosion had taken place with the cooperation of both the police and local authorities and had followed all the health and safety procedures.

He added that safety marshals were present and that the area had been cordoned off.