Depends what year.

Current model = No, not from factory.
There are a couple of U.K dealers doing what appear to be good conversions.

http://www.americanpickuptrucks.com/
Can't find the other one

D.I.Y if you wish
http://www.right-hand-drive.co.uk/05_mustang.htm

.

Previous models, no offical conversions except Ford U.K did some conversions on some 70's models.
Otherwise any conversion is an amateur job, and some are very amateur.