As forces loyal to Libyan strongman Col. Moammar Gadhafi continue to battle rebels, thousands of civilians have been caught up in the fighting.
Asked by a member of Parliament whether ground troops might be required to protect safe havens or civilians or for humanitarian purposes, Fox said it was "something we may have to look at," The Daily Telegraph reported.
"The basis on which we operate is if there is any new development which we believe is different from that which has gone before we would seek advice from the attorney general," Fox told members of the Commons Defense Committee.
U.S. President Barack Obama has ruled out sending American ground forces to Libya and Fox Wednesday repeated there is "no intention to deploy any British troops on the border with Libya." Britain has about 10,000 troops in Afghanistan, where British forces have been active since 2003.
An F-16 aircraft participating in the NATO-led operation to protect Libyan citizens was involved in what NATO called an incident on landing in Italy Wednesday.
The pilot ejected safely and his condition was being assessed, NATO said on its Web site. The nationality of the aircraft was not released.
The cause of the incident at Naval Air Station Sigonella was being investigated by Italian police.
NATO also said an unmanned aircraft was used in Tripoli Tuesday to destroy a surface-to-air missile system. Operators of the Predator drone delayed the firing until civilians left a nearby football field.
Because the drone strikes will continue, NATO said it has asked civilians to distance themselves from Gadhafi regime forces, installations and equipment whenever possible.
Rebels hunkered down in Misurata said much of the city resembled a wasteland Wednesday after NATO warplanes hit vehicles of Gadhafi forces advancing toward to port city.