Supermarket staff are warned to be on the lookout for terrorists trying to bulk-buy fireworks to build bombs

• Employees told to watch out for fireworks customers who appear nervous 
• Staff are also warned over those who seem uninterested in safety advice
• National Counter Terrorism Security Office's guidance is posted in stores

Supermarket staff across Britain have been warned to watch out for terrorists trying to bulk buy fireworks to build bombs.

Employees have been warned to be on the lookout for customers who appear nervous and avoid communication or seem uninterested in safety advice.

Guidance from the National Counter Terrorism Security Office (NaCTSO) has been posted in stores across the country to help foil any potential firework terror attacks.

'Know your customer': Guidance from the National Counter Terrorism Security Office has been posted in stores across the country to help foil any potential firework terror attacks

A poster says: 'Fireworks have been misused by terrorists. Your vigilance in reporting suspicions can help the authorities detect and disrupt such activities.'

It adds that staff should watch out for people trying to bulk buy fireworks with cash and those who avoid giving personal details such as their address.

Employees should also be aware of customers asking for unusual packaging or delivery methods, or being vague on the intended use of the fireworks.

One worker from a Sainsbury's branch in West Yorkshire told the Daily Mirror: 'We have all been briefed to watch out for terrorists buying fireworks.

'There was a poster on the wall in the staff room and when I asked a manager about it he said we should be looking out for people who could be supporters of Isis.'

'He said we should report anyone we thought was suspicious, such as people coming back several times to get more fireworks or wanting to buy very large amounts and using cash.'

The distinctive black and yellow poster, which has the heading 'know your customer', was produced in association with the British Fireworks Association.

A spokesman for the National Police Chiefs' Council said NaCTSO 'provides a range of industries with advice to remind staff to be vigilant, help them spot suspicious activity and advise them on how to respond'.