The head of MI5 has issued a new warning over al-Qaeda.

Speaking in London last night, Eliza Manningham-Buller, director general of the security service, said the food sector may now present a "very attractive target for terrorists".

A spokeswoman for the Home Office told ePolitix.com: "The threat from terrorism remains real and serious. We have the same state of heightened readiness and concern that we had this time last year.

"Much has been done since September 11 2001 to thwart attacks and to damage terrorists' abilities. But no country is immune from attack, and it simply is not possible to guarantee against attacks in the future.

"The British public are mature and sensible and have lived with the threat of terrorism for many years. The public must be treated like adults and given information about the threats that we face.

"The speech by the DG is a good example. As the DG part of our ability to tackle the threat from terrorism requires the support and cooperation of the public.

"Where threats are specific, we seek to thwart them. Where they are general, we seek to analyse them, and take whatever response we believe to be necessary to ensure the protection of the public.

"The government will never hesitate to issue a warning if it is the best way to protect any community or venue facing a specific and credible threat.

"Advice would be issued immediately if the public needed to take specific action. Public safety is our absolute priority."

Forum Response: British Retail Consortium

David Southwell, spokesman for the British Retail Consortium, told ePolitix.com: "Today's press coverage is a textbook case of a 'Don't panic Captain Mainwaring' media response.

Customer safety is the number one priority of the food industry - it always has been - so the only thing to be surprised about yesterday's announcement from MI5 was if the retail sector were not well aware of the potential risks post-9/11 and in regular, formal updates contact with the security services.

"Retailers have regular, formal updates and briefings and from the security services and regularly review alerts status and security procedures.

"From the current threat assessments from the security services, there is no evidence of a specific threat.

"Again, you'd only be surprised if retailers and others in the food chain were prepared to talk in more about our anti-terrorist activities as this may actually assist terrorists.

"However, it is worth noting the UK retail sector has developed world-leading security measures over the last 30 years as a response to both potential Republican terrorism and criminal extortion. These measures have allowed for us to be in a very strong position to adapt to potential threats post-9/11."