IT staff travelling abroad are being targeted by foreign spies in an attempt to steal cutting-edge technologies and research, according to MI5.
MI5 warns that many countries still make extensive use of espionage against the UK.
It said foreign spies will seek intelligence on cutting-edge technologies and associated research and development data, and will target scientists, employees of high-tech companies and business people to get it.
"The covert or unauthorised acquisition of our scientific research, industrial and computer technology can also harm the UK's defences, economic well-being and national infrastructure," the agency warns.
It said travellers should be aware of local laws on social and sexual behaviour and make sure they obey them and avoid any "compromising behaviour which could make you vulnerable to subsequent blackmail" -- the so-called 'honey trap' approach.
Warning signs that spies are grooming a traveller for recruitment may include requests to meet in hotels and restaurants rather than at work, and moves to bring relationships onto a social footing.
Alternatively it may take the shape of requests for openly available information which, when received, is rewarded with small gifts or payment.
MI5 warns that lavish hospitality and flattery may also be used to soften up a target for recruitment who may then feel obliged to co-operate rather than offend the hosts.
The agency said travellers should be aware that people they come into contact with professionally could later be interviewed by the local security service.
MI5 said spies will use a variety of techniques to target travellers including intercepting telephone calls, monitoring computer equipment and emails, planting eavesdropping devices and searching hotel rooms -- including safes.
Travellers are also warned to avoid discussing sensitive aspects of your business in areas where conversations could be overheard, or on the telephone.
"Eavesdropping devices could be used or your telephone calls intercepted. International calls are particularly vulnerable to remote interception," the agency warns.