BAA Spokesperson:

"The performance of the Terminal 4 baggage system has today been reduced by an ongoing software problem. Whilst every effort is being made to rectify the problem over night and contingency plans have been put in place, there is a risk that operations out of Terminal 4 may be affected tomorrow.

Passengers travelling through Terminal 4 tomorrow should check with their airlines before coming to the airport to understand the potential impact on their travel plans.  In particular, passengers should consider minimising the amount of hold luggage they check in.

Please be assured that our staff will be working through out the night to minimise any potential disruption tomorrow."