An armed robber who held up staff at a Norwich building society is believed to have dropped the knife he used - as police chased him through city gardens.

After robbing the Norwich and Peterborough Society branch in Plumstead Road yesterday, the suspect led police on a chase through nearby gardens, where police think he dropped the weapon.

Police arrest man after knifepoint raid at Norwich and Peterborough Building Society

Officers have been searching gardens in the Dugard Avenue and Riseway Close area today, but appealed to people living in not to touch the weapon they believe he dropped, if they find it.

Police were called to the Norwich and Peterborough Building Society at about 4.50pm, following reports of a robbery in progress.

A customer, who had been inside the bank when the robber entered, managed to leave to raise the alarm and dialled 999.

Staff were threatened by the suspect who demanded money while holding a small knife. The robber got away with a quantity of cash before fleeing the scene on foot.

Police went to the scene and the surrounding area to search for the suspect.

A man was spotted acting suspiciously in Borrowdale Drive and, when he saw police, he ran, sparking chase through back gardens in the area of Dugard Road and Riseway Close.

The man, aged 42, was detained after being tasered by police and was arrested at 5.50pm. He was quizzed last night and remains in police custody.

But police believe the weapon he used, along with items of clothing, were dropped during the chase and appealed for people to look out for them.

Detective Inspector Richard Graveling, from Norwich CID, said: 'We know this man has been in people's back gardens as he ran from police and the concern is that people may not realise there is a potentially dangerous weapon in their garden.

'I would encourage people living in the area to be aware of this incident and check areas outside. If anyone comes across clothing or the weapon please do not touch it and call police immediately.'

Officers carried out a brief search of the area last night and further searches were being carried out today in a bid to recover the knife.

Last night, DS Tom Smith, from Norwich police, praised the quick-thinking of the customer who raised the alarm.

He said: 'Fortunately no one was injured during the incident although staff have understandably been left shaken.

'The prompt call from the bank customer meant we were able to dispatch officers to the scene immediately with details on the man's description which ultimately led to the swift arrest of the suspect.

'We're still keen to hear from any witnesses and I would urge people who may have been in the area at the time to come forward.'

Anyone with information concerning the armed robbery or the items he is believed to have dropped during the chase should contact Norwich CID on 101.