Businesses in Norfolk and Suffolk are being warned to stay alert after a spate of cold callers pretending to be a police sergeant.

A company in Harleston, in Norfolk, received a call on Monday, September 17 from someone claiming to be Sergeant Mark Shepherd from Suffolk police.

They asked to speak to the director as he 'was doing a campaign involving going into schools and talking about safety issues and requesting sponsorship'.

When the staff member declined the caller hung up.

A further call on Wednesday, September 26 to a business in Hadleigh, in Suffolk, also claimed to be Sergeant Mark Shepherd.

He said he was from the media department of the police and was asking for charity donations. When challenged he said he was a freelancer and provided an invalid phone number.

Later in the day another call was received from a man to a sister company which shares the same address and was answered by the same member of staff.

The man was challenged after he repeated his request to speak to a director and he then gave his name as Steven Gerrard before the call was ended.

Officers have advised businesses to:

• Never give out personal information about your bank account to anybody over the phone.

• If someone calls claiming to be a police officer, ask for their identification number and police force.

• Hang up and call 101 using a different phone. If you can't use a different phone, wait at least five minutes before calling back. A genuine police officer will not mind waiting while you check.

• Police and banks will never ask you to give out personal details such as account numbers or PIN numbers.

• If you have given out information which could compromise your bank account security in any way, call your bank to cancel your cards as soon as possible.

• Never hand over money to someone at the door to be sent off elsewhere.

Anyone with concerns about such calls should contact Norfolk police on the non-emergency number 101 or 999 if a crime is in progress.

Alternatively, contact Action Fraud on 0300 123 2040.